Study under review: Green tea catechins prevent lowdensity lipoprotein oxidation via their accumulation in low-density lipoprotein particles in humans
Introduction
Atherosclerosis is a disease characterized by the thickening and narrowing of arterial walls due to the progressive buildup of plaque. Since atherosclerosis is a chief contributor to cardiovascular disease (CVD), the leading cause of death worldwide, there is great interest in finding ways to slow its development.
While the pathogenesis of atherosclerosis is only partially understood, mounting evidence [1] suggests that the oxidation of low-density lipoproteins (LDL) may play a pivotal role (as shown in Figure 1). Accordingly, protecting LDL from oxidation could potentially be a sound strategy in slowing its progression.
Figure 1: How oxidized LDL may contribute to athersclerosis
Adapted from: Stein et al.Int J Mol Sci. 2015.
A growing number of people are turning to dietary antioxidants to minimize oxidation. Lending credence to this trend, epidemiological [2] evidence [3] has displayed a positive association between use of dietary antioxidants and a reduced risk of coronary heart disease. This has been ostensibly corroborated by the results of animal studies [1] which indicate the effectiveness of antioxidants in reducing the severity of atherosclerosis. Although the few human trials [1] that exist remain equivocal, most used vitamin E or beta-carotene as their antioxidant. More clinical trials analyzing the effect of a wide range of antioxidants are needed to determine if antioxidants, either through food or supplementation, can help prevent or mitigate conditions like atherosclerosis.
Green tea is a popular beverage, in part due to its purported health benefits [4]. These health benefits may be attributed to green tea's high concentration of polyphenols, which may have antioxidant properties [5] The major type of polyphenol found in green tea are known as catechins. The four main types of catechins are epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and epigallocatechin-3-gallate (EGCG). Researchers have proposed a molecular mechanism through which EGCG, the most abundant catechin in green tea, may reduce endothelial inflammation [6] by stimulating the cell's own defense system against oxidants.
Moreover, the authors of the study under review previously found [7] that directly adding green tea catechins to isolated LDL particles inhibits oxidation in a test tube (in vitro). Although these findings are promising, what happens in test tubes doesn't always replicate in humans. As a result, a few years later the authors extended their findings into humans [8], reporting that an acute intake of five grams of green tea powder led to an increase in plasma catechin levels and increased the resistance against LDL oxidation in healthy people. However, even though the increase in plasma catechin levels was simultaneous with a reduction in LDL oxidation, there was still a possibility that green tea protected LDL particles from oxidation through a mechanism unrelated to the catechins.
Therefore, the purpose of this study was to observe whether or not green tea catechins are incorporated into plasma LDL particles and thereby provide protection against LDL oxidation, both in vitro and in humans.
The oxidation of low-density lipoproteins (LDL) seems to play a pivotal part in the development of atherosclerosis, a chief contributor to cardiovascular disease (CVD). Recent studies have reported that green tea, which has a high concentration of antioxidants in the form of catechins, has the potential to reduce LDL oxidation. This study was designed to test green tea catechin incorporation into LDL particles, and hence protection against LDL oxidation.
Who and what was studied
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Men who pop supplements to boost testosterone, rev up libido, or even prevent cancer may not be getting what they think they're getting.
A lot of American guys use dietary supplements — an estimated 47 percent — and they're spending a ton of money on them. In 2011, American consumers spent $30 billion on these over-the-counter nutritional items — 42 percent for vitamins and minerals, 17 percent for herbal or botanical supplements, and 12 percent for sports nutrition products.
But these billions are going for stuff that's neither FDA-regulated nor proven to be safe or effective. Supplement makers can say whatever they want about their products as long as they don't claim to prevent, cure, or treat disease. And a man's decision to use supplements may be motivated more by wishful thinking than by hard evidence. Guys who are hopeful that supplements will bulk them up, maybe prevent disease, or, more likely, boost their bedroom performance, should be especially wary of these 7 supplements.
Beta-Carotene and Vitamin A: Dangerous for Smokers
Beta-carotene is an antioxidant responsible for the deep red-orange color found in carrots, sweet potatoes, and cantaloupe. The body converts beta-carotene into vitamin A, a fat-soluble nutrient that protects cells from damage and that we need for eye, immune system, and skin health.
It's a great example of a nutrient that in the 1960s and 1970s was thoroughly investigated in animal studies, and even in some human observational studies that suggested "greater amounts of beta-carotene intake would result in a lower risk of cancer," said Howard D. Sesso, ScD, MPH, an associate professor of medicine at Harvard Medical School in Boston.
However, these trials testing individual beta-carotene supplements – as well as vitamin A – offered "pretty compelling evidence that the potential benefits were not real," said Dr. Sesso. Some studies even suggested an increased risk for lung cancer in people who took them, especially in men who smoke, he added. Toxicity can result from high doses of vitamin A because the body stores rather than gets rid of excess amounts.
"I'm not aware of any real reasons why someone would want to still consider taking these supplements," Sesso said.
Selenium: Higher Prostate Cancer Risk
Selenium is a trace mineral Americans usually get enough of from breads, grains, meat, poultry, and fish. It's another antioxidant that's been evaluated in high doses to see if it could protect against chronic diseases like cancer. However, "the selenium trial that was done years ago in people to prevent recurrence of skin cancer actually increased the recurrence of skin cancer," said Alan Kristal, DrPH, a faculty member in the Public Health Sciences Division at the Fred Hutchinson Cancer Research Center in Seattle.
Further analysis suggested a prostate cancer risk benefit, said Dr. Sesso, which helped propel the launch of the SELECT trial, the largest prostate cancer prevention study to date that tested the effects of selenium and vitamin E. However, SELECT found no benefits in prevention of prostate cancer, said Dr. Kristal, one of the study's authors. And the most recent analysis even showed increased prostate cancer risk in some men.
"There don't appear to be any compelling results or reasons to be taking selenium to prevent prostate cancer, or at least cancer in general, at this time," Sesso advised.
Kristal agrees. "Why would you take selenium if it's not going to help you?"
Vitamin E: No Impact on Heart and Cancer Risk
Vitamin E is a fat-soluble antioxidant found in nuts, seeds, and vegetable oils that's also been studied extensively for disease prevention. Substantial research had "suggested that vitamin E would reduce not just cancer risk, but also cardiovascular disease risk," said Dr. Sesso.
However, as Dr. Kristal explained, vitamin E failed to show benefits in people: "It looked good and it worked in a test tube, but it had absolutely no impact when tested in humans." Sesso agrees. Most of the trials "found that there doesn't appear to be any obvious benefits to taking individual vitamin E supplements."
But research is mixed on the vitamin's effects on prostate cancer. In contrast with the SELECT trial, which found an increased risk for the disease in men who took selenium and vitamin E, the Physicians' Health Study II (PHS-II) "found no effect on prostate cancer at all," said Sesso, one of the authors of PHS-II. "We don't believe that there are any obvious risks for vitamin E supplementation and prostate cancer" if you consider all of the evidence, he explained.
Still, Sesso advises that "there's no reason to take it, either. It's not because of potential risk, but just because of lack of benefit, also."
Yohimbe: A Flop for Erectile Dysfunction
The extract from the bark of yohimbe, an evergreen tree found in western Africa, is sold over-the-counter, but its active ingredient, yohimbine, is available only by prescription. Yohimbe bark supplements claim to help erectile dysfunction (ED), even though "very few studies show that it's very useful," said Keith D. Bloom, MD, a urologist at Baylor Medical Center in Irving, Texas.
According to Dr. Bloom, supplements like yohimbe aim to mimic, to some degree, what Viagra, Cialis, and Levitra do, which is to increase blood flow, but "they just don't do it nearly as well as the prescribed medications do, they don't do it as safely, and they're unregulated," he said.
Another issue is that yohimbe doesn't mix well with some commonly prescribed drugs. "It can interact with other medications that patients may be on for blood pressure," said Bloom. "It may also interact with other stimulants and certain antidepressants." Yohimbe also causes some unpleasant and even risky side effects, including elevated blood pressure, increased heart rate, dizziness, flushing, nausea, and headache.
"There's really no good reason to be taking it at all," Bloom asserted. "I wouldn't recommend it to anyone."
Horny Goat Weed: An ED Aid That May Contain Arsenic
Horny goat weed is a plant whose active ingredient, epimedium, is purported to help ED.
"This weed supposedly earned its name after a shepherd noted increased sexual behavior in goats who had eaten it," said Dr. Bloom. According to the urologist, the supplement is thought to increase blood flow in the penis, but it's never been studied in people.
Because these types of male enhancement products are not FDA-regulated, "you don't know what you're getting, you don't know how much of the supplement you're actually getting, and you don't know what other fillers are being used to formulate the supplement," Bloom cautioned. "Companies aren't required to tell you everything they put into a supplement." Potential problems can include allergic reactions to unidentified ingredients and contamination with dangerous substances like lead and arsenic.
"The most important thing that I would express is that if you have ED, it's best that you see a doctor to rule out more serious health conditions such as heart disease and diabetes," Bloom said. "That's a very, very important takeaway, rather than treating yourself."
DHEA: A Downer for Good Cholesterol
DHEA — short for dehydroepiandrosterone — is a steroid hormone that the body makes and converts into sex hormones. The body's levels decline naturally starting at about age 30. Some men take DHEA supplements containing a synthetic form sourced from soybeans to replace the hormone. Purported benefits include libido- and testosterone-boosting effects.
"DHEA may have some vasodilator qualities, meaning it will increase blood flow, but the main reason people take it is to potentially increase androgen or testosterone-like compounds and estrogen," said Dr. Bloom. "So it's thought that it can increase libido in men and women…but there's no great data on that." Bloom cautioned that with steroidal supplements like DHEA, "there have been quality-control issues with over-the-counter preparations, in terms of how much active ingredient is added."
DHEA supplements can present other risks. "There are side effects with palpitations and worsening of the cholesterol profile," he warned, which means a "lowering of the good cholesterol [or HDL] that you want to be elevated." He's also concerned that the supplements "can suppress your body's potentially normal production of DHEA."
For men still considering DHEA supplements, proceed with caution: They "should not be taken without supervision," advised Bloom.
Tribulus Terrestris and Tongkat Ali: Don't Boost Testosterone
Tribulus terrestris and Tongkat ali are flowering plants that make up two of the more common ingredients found in so-called testosterone-boosting supplements. Not much is known about either plant's effects on testosterone levels. Although Tribulus terrestris"may increase libido in animal studies…the only human studies I found showed it did not increase testosterone," said Dr. Bloom.
"I tell patients who ask about supplements that if they were as effective as they claimed, we would use them routinely," he said. "It would be our standard of care."
The most effective and established ways for lowering the risk and transmission of coronavirus disease are social distancing and regular handwashing. However, taking vitamins and supplements may also help your body increase immunity and mount an immune response to infections.With an extensive brand of multivitamins in the market, which then is the best in the Philippines? In our Best of Health series, we introduce the11 Best Multivitamins in the Philippines, providing quality recommendations based on your budget and needs.
This article was last updated on 30 November 2021.
Table of contents
Best Multivitamins in the Philippines (Summary)
Age-adjusted formula for healthy ageing: Centrum Silver Adults 50+
Use the code TWVEC for existing customers to get 10% off and TWVNC for new customers to get a $5 discount
Promo is redeemable with a minimum spend of $45 USD for TWVEC and $30 USD for TWVNC
With 25 nutrients and antioxidants for overall health benefits: Centrum Advance Multivitamins + Minerals
Best for boosting energy and immunity: Enervon Multivitamins
Anti-stress formula with skin-repairing and immunity building nutrients: Stresstabs Multivitamins + Iron
Neurogen-E
Conzace Multivitamins
Best for athletes and trainers: MuscleTech Platinum
Berocca Orange Energy Vitamins Effervescent
HealthFusion Multivites for Adults and Kids
Great value for money: Kirkland Signature Daily Multi 500 Tablets Vitamins & Minerals
Nature's Way Alive! Max 6 Daily Multivitamin
11 Best Multivitamins in the Philippines
1. Centrum Silver Adults 50+
Image Source: E Vitamins
Age-adjusted formula for healthy ageing
As we grow older, our body changes along with our age. But that does not necessarily mean that we should slow down, we just need to make sure that the nutrients we get are in line with the requirements for our ageing body. And that is where the Centrum Silver Adults 50+ comes in. Specially crafted for adults aged 50 years old and beyond, Centrum ensures that you age healthily and gracefully. The multivitamin comes as smooth-coated tablets, so they are quite easy to swallow even if you experience throat issues. However, if you have pre-existing medical conditions like diabetes and hypertension or are pregnant, it is always better if you consult with your doctor before you decide to take the multivitamins.
Packed with all the essential nutrients
The Centrum Silver Adults 50+ is made with high-quality ingredients to help promote heart health, support brain function and maintain healthy eyes in older adults. It even contains Centrum's highest level of vitamin D3, which is the preferred form of Vitamin D in supporting strong and healthy bones. So overall, the multivitamins target common issues in ageing adults, keeping their health and wellness in check.
Why buy this:
Verified non-GMO and gluten-free
Contains more than 12 essential daily vitamins, 13 minerals and nutrients
Easy to swallow
Iron-free multivitamins
Available in two sizes
E Vitamins promo code:
Use the code TWVEC for existing customers to get 10% off and TWVNC for new customers to get a $5 discount Promo is redeemable with a minimum spend of $45 USD for TWVEC and $30 USD for TWVNC
2. Centrum Advance Multivitamins + Minerals
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Centrum's products, known for their iconic tagline "from A to Zinc," seek to help adults and children obtain the nutrients they need every day. They take pride in having a nearly complete formulation of all vitamins and minerals that are considered to be essential for a range of health benefits. If you want something to take once a day, Centrum Advance Multivitamins is the tablet for you. It packs a lot of punch into a single medium-sized tablet that is easy to swallow with no harsh aftertaste. Best of all, it's accessible at most supermarkets and pharmacy stores!
With 25 nutrients and antioxidants for overall health benefits
Centrum Advance is a daily multivitamin in the Philippines that has been specifically developed to provide a comprehensive mix of vitamins, minerals, and antioxidants to help protect your entire body. It incorporates cutting-edge nutritional science to support your health, protect your heart, eyes, immune system, and much more. Furthermore, it is said to be suitable for active men and women under the age of 50, with the product having 10 Immunity-boosting vitamins, minerals, and antioxidants to supposedly promote healthy immune function, as well as vitamins A, C, and biotin to help maintain healthy eyes and skin. It also contains B group vitamins, which are said to help with energy production.
Despite being high in nutrients, Centrum tablets are relatively mild with lower dosages of ingredients, so there's no need to worry about overloading. With the low amounts of a-z components, you will not notice much of a difference after taking them regularly, and they will not affect your everyday lifestyle. Overall, this multivitamin brand is good for general immunity, especially during a pandemic.
Why buy this:
Packed with A-Z nutrients
Widely available at supermarkets and drugstores
With up-to-date nutritional science to support your health
3. Enervon Multivitamins
Image Source: Shopee
Best for boosting energy and immunity
Enervon is a popular multivitamin brand in the Philippines that contains Vitamin C for boosted immunity and Vitamin B for increased energy. It can also be used to address vitamin B complex and vitamin C deficiencies.The tabs supply your body with essential vitamins when it is difficult to meet the body's requirements due to insufficient food intake or poor diet, which is common among working people. So, if you want to boost your energy and immunity, you should certainly consider taking Enervon daily.
On top of that, understanding the contents of this supplement actually helps you save some cash and gives good value for money. Since this is a multivitamin, it is far less pricey than getting a single supplement containing only Vitamin C, Vitamin B complex, or Calcium.Enervon provides all of these nutritional supplements at a low price point to give you more energy and immunity so you can perform the things you need to do every day!
Why buy this:
Affordable
Can help with vitamin C and B complex deficiencies
Helps promote increased energy
Widely available at supermarkets and drugstores
One of the most popular multivitamin brands
4. Stresstabs Multivitamins + Iron
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Anti-stress formula with skin-repairing and immunity building nutrients
Stresstabs is definitely the best multivitamin for you if you're currently on WFH and always stay up late at night. The supplements are high-potency B-complex vitamin formulations that help restore what stress has taken away.It may also boost your energy levels and help you to accomplish tasks that stress might otherwise stop you from doing. Additionally, it promises to help you deal with stressful situations more efficiently!
Even better, Stresstabs is intended to give long-lasting continuous energy. Rather than giving an energy boost like other multivitamins, these tablets give essential minerals to help your body naturally battle against physical stress.In fact, many consumers claim that it provides them with the energy they need and improves their memory retention! Plus, skin-repairing elements such as iron can help your skin appear better even under extreme stress.
Why buy this:
Helps strengthen immunity and fight the stress effects
Widely available at supermarkets and drugstores
Can help replenish the skin
5. Neurogen-E Multivitamins
Image Source: Unilab Philippines
If you need supplements for your B-vitamins and vitamin E needs, look no further than Neurogen-E. Neurogen-E is a multivitamin combining Vitamin B-Complex and Vitamin E that promotes healthy nerves and relieves the symptoms of nerve damage liketusok-tusok, ngalay, and manhid to make your nervous system healthy. Compared to other OTC products, each Neurogen-E caplet contains 5x more Vitamin B12, 3x more Vitamin B1. It's a good thing since with all of the perks B-complex vitamins give, taking them is a no-brainer because they can help you step up your game every day!
Why buy this:
Helps promote healthy nerves
Can provide relief against nerve damage symptoms
With 5x more B12 and 3x more B1 vs. major OTC brands
Also used for treatments against B-complex deficiencies
6. Conzace Multivitamins
Image Source: Unilab Philippines
Skincare should also be an essential part of your overall health regimen, and you can actually look healthy and youthful by ensuring that you take enough vitamins! Conzace Multivitamins not only improve your immunity but also make you look fresher.It has the highest levels of zinc, vitamins A, C, and E, and it has been proven to boost immunity by 140 percent while maintaining skin and hair in perfect condition. In fact, several people claim that taking these vitamins has helped them minimize acne outbreaks! So, if you want a multivitamin that will help you strengthen your immune system while avoiding maskne breakouts during the pandemic, Conzace is the best choice.
Why buy this:
Specially formulated to give you healthy hair and skin
Can strengthen the immune system by 140% vs. no supplementation
7. MuscleTech Platinum Multivitamins
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Best for athletes and trainers
Physical activity and exercise could be effective treatment techniques for improving general health, and when combined with daily vitamin intake, they can be even more beneficial. If you regularly go out and exercise, we recommend MuscleTech Platinum Multivitamins, since this vitamin is developed to promote overall health in athletes.Intense trainers like you may lose essential nutrients as a result of your training, so these caps offer the most important micronutrients to promote overall health and physical performance. Vitamins A, C, D, E, and B are included and digestive enzymes and essential amino acids. Overall, it's a very comprehensive supplement for physically active folks!
Why buy this:
High-potency vitamins & minerals
Scientifically designed for physically active individuals
Supports a strong health foundation for optimal performance
8. Berocca Orange Energy Vitamins Effervescent
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Taking tablets or pills regularly can become boring and repetitive, but Berocca spiced things up by creating vitamins in juice form. Berocca Energy Vitamins Effervescent is an energy supplement that can help you overcome struggles in your everyday life and provide you with a consistent supply of energy throughout the day.These tabs are high in vitamins and minerals, including B1 and B2 to help in energy release, B12 to help with fatigue and exhaustion, and Vitamin C and Zinc to help strengthen the immune system and keep you in prime shape every day. Simply drop a tablet into a bottle or glass of water, wait for it to fizz, and enjoy!
Why buy this:
Sugar and caffeine-free
Suitable for vegans
Packed with 11 vitamins and minerals
9. HealthFusion Multivites for Adults and Kids
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While many young children (and adults) despise taking vitamins and prescriptions, the Healthfusion Multivites is a delicious alternative to conventional difficult-to-swallow pills. It's marketed in the Philippines as a delicious multivitamin gummy that combines essential minerals and natural fruit flavors.Moreover, this comprehensive multivitamin is formulated specifically for children and contains vitamins A, C, D, E, B6, B12, B5, folic acid, iodine, zinc, and biotin. With these fruity gummies, you can truly have a fun and delightful way of keeping your family healthy!
Why buy this:
The most complete gummy multivitamin in the country
FDA-Certified, GMP & ISO approved
Halal, gluten-free and vegan-friendly
No use of artificial color, flavor, or sweetener
Suitable for adults and kids
10. Kirkland Signature Daily Multi 500 Tablets Vitamins & Minerals
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Great value for money
Kirkland Signature Daily Multi is carefully formulated to provide a comprehensive range of vitamins and minerals to help fill nutrient gaps when you can't consume a proper amount of food to meet the recommended daily intake. It includes calcium and vitamin D to strengthen bones and teeth, lutein for eye health, vitamin E for antioxidant activity, and many other nutrients.We highly recommend getting this product if you want to save some cash and avoid the trouble of running to the drugstore regularly to replenish your vitamin supply. Each bottle has 500 tablets (approximately P3 per piece) which can last you months!
Why buy this:
Value size; perfect for families
Provides a full spectrum of vitamins and minerals
Scientifically formulated for overall good health
11. Nature's Way Alive! Max 6 Daily Multivitamin
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If you've been taking vitamins for a long time, it might be time to switch to food-based supplements.Nature's Way Alive! Max6 Potency Multivitamin is the ultimate nutritional energy source, containing a wide assortment of daily essentials, whole food concentrates, phytonutrients, and antioxidants to nourish, protect, and energize your body.Every serving claims to provide natural energy from vitamins and minerals for your overall wellness. However, "food-based" does not imply that you are consuming the equivalent of fresh fruit and vegetables. Nature's Way produces these formulations by combining concentrated and dehydrated fruits, vegetables, herbs, and spices.As a result, they deliver nutrients that are as close to their natural state as possible!
Why buy this:
Ultra-potency multivitamin for daily energy metabolism
Gluten-free
No artificial colors, flavors, or preservatives.
We hope that our guide on the 11 Best Multivitamins in the Philippines has helped you pick the best supplement for your health and diet needs. Please share this with your family and friends if you have found it useful!
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Vitamin A should be an integral part of every person's diet. It plays vital roles in your body by helping to maintain your vision, skin health and even your immune system's ability to work properly. But it's important to consume the right amount; vitamin A can be harmful when your body gets too much of it. Learn more about vitamin A, including what it does, where to find it and what happens when you get too much of it.
Vitamin A is actually a group of fat-soluble vitamins like retinol, retinal and retinyl esters, all of which have various health benefits. Vitamin A is particularly important in the maintenance of vision — especially your ability to see in low light. Your body converts this vitamin to retinal, which combines with other molecules to form rhodopsin. This is the protein principally responsible for your eyes' absorption of light. If you're worried about your vision getting worse over time, make sure you get enough vitamin A. It's a good way to strengthen your sight naturally.
Photo Courtesy: Nastasic/E+/Getty Images
Consuming sufficient amounts of vitamin A can also work wonders for your immune system. Vitamin A promotes the production of white blood cells, particularly T cells, which eliminate viruses and bacteria from your body. Vitamin A also stimulates the production of special T cells called regulatory T cells. These help to reduce the risk of your body attacking its own healthy cells, which is what happens with some autoimmune diseases. Furthermore, vitamin A fortifies the linings of your respiratory, intestinal and urinary tracts, along with your skin and mucous membranes. It also sends additional immune cells there to prevent bacteria from entering your body and causing an infection.
Vitamin A is also involved in the maintenance of healthy skin by helping immature skin cells age properly into mature skin cells. It reduces sebum production, which can be problematic in oily skin. In fact, Isotretinoin is a common prescription-only vitamin A derivative used as a treatment for acne.
Vitamin A can also contribute to improved bone growth, cell division and cell differentiation. It even promotes reproduction and is a healthy supplement for people who are breastfeeding.
Food Sources of Vitamin A
Vitamin A is quite easy to come by naturally. Many of the most basic staples in our diets — meat, eggs, milk and cheese, for example — are excellent sources of vitamin A. Other specific animal sources have high vitamin A levels as well, such as kidney and liver. However, it's important to note that some of these foods have high cholesterol and saturated fat levels, so be sure to keep a healthy balance of these in your diet if you choose to eat them.
Photo Courtesy: GMVozd/E+/Getty Images
Vitamin A exists as either preformed vitamin A or as provitamin A carotenoids. Preformed vitamin A is found in animal and dairy sources. Provitamin A carotenoids include beta-carotene and alpha-carotene, which your body converts into vitamin A and other derivatives. Beta-carotene is found in foods like carrots, pumpkins, sweet potatoes, cantaloupes, grapefruits, spinach, broccoli and apricots. As a general rule, the more vibrant the color of a fruit or vegetable is, the more beta-carotene it contains. As a bonus, you won't have to worry about the fat or cholesterol content in these foods.
Side Effects of Too Much Vitamin A
Getting the right amount of vitamin A in your diet shouldn't have any negative side effects. However, a vitamin A deficiency can lead to health issues over time. If you don't get enough vitamin A, you could develop vision problems. Plus, your immune system could weaken, leaving you susceptible to infectious diseases.
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Perhaps even more serious are the side effects of consuming too much vitamin A, also known as hypervitaminosis A. Initially, too much vitamin A can cause headaches, dizziness, nausea and even vomiting. Because vitamin A is fat-soluble, it tends to get stored in your liver if you consume too much of it, which can lead to liver problems and even liver failure. There's also evidence that getting excess vitamin A can cause osteoporosis and bone fractures.
In particular, pregnant people must be careful about their intake of vitamin A, as getting too much vitamin A can cause birth defects. Pregnant people shouldn't eat foods that are high in vitamin A, such as pate and fish liver oil. In general, babies and small children are more sensitive to vitamin A overdoses and deficiencies, so it's important to closely monitor their daily vitamin A consumption, too.
Taking Vitamin A: Daily Dosage Recommendations
According to the Institute of Medicine Food and Nutrition Board, most adult men should consume around 900 micrograms (mcg) of vitamin A per day, and women should have around 700mcg per day. The recommended daily intake is lower (750–770mcg per day) in pregnant people and higher (1200–1300mcg per day) for people who are breastfeeding.
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The daily dosage for children varies with age. From 0 to 6 months, infants should have 400mcg per day, after which they should consume 500mcg per day until they reach the age of 1. Children 1 to 3 years of age should get 300mcg per day, while those from 4 to 8 years of age need 400mcg per day. Those from 9 to 13 years old need 600mcg each day. Daily recommendations for children don't change based on gender.
These dosage requirements are general guidelines. Individuals may have differing daily recommendations for vitamin A, depending on their health status and lifestyle. Most people can get a sufficient amount of vitamin A simply by eating a balanced diet. Consult a doctor before taking any vitamin A supplements or changing from the recommended dosage for your age and sex.
In summary, it's important to be aware of the foods that'll give you an adequate supply of vitamin A. Provided you have a balanced diet, you might not need to take vitamin A supplements. Be aware of foods containing high levels of vitamin A, and avoid eating too much of these, particularly during pregnancy.
Vitamin C is an essential vitamin, meaning your body can't produce it. Yet, it has many roles and has been linked to impressive health benefits.
It's water-soluble and found in many fruits and vegetables, including oranges, strawberries, kiwi fruit, bell peppers, broccoli, kale, and spinach.
The recommended daily intake for vitamin C is 75 mg for women and 90 mg for men (1).
While it's commonly advised to get your vitamin C intake from foods, many people turn to supplements to meet their needs.
Here are 7 scientifically proven benefits of taking a vitamin C supplement.
Vitamin C is a powerful antioxidant that can strengthen your body's natural defenses (2).
Antioxidants are molecules that boost the immune system. They do so by protecting cells from harmful molecules called free radicals.
When free radicals accumulate, they can promote a state known as oxidative stress, which has been linked to many chronic diseases (3).
Studies show that consuming more vitamin C can increase your blood antioxidant levels by up to 30%. This helps the body's natural defenses fight inflammation (4, 5).
SUMMARY
Vitamin C is a strong antioxidant that can boost your blood antioxidant levels. This may help reduce the risk of chronic diseases like heart disease.
Approximately one-third of American adults have high blood pressure (6).
High blood pressure puts you at risk of heart disease, the leading cause of death globally (7).
Studies have shown that vitamin C may help lower blood pressure in both those with and without high blood pressure.
An animal study found that taking a vitamin C supplement helped relax the blood vessels that carry blood from the heart, which helped reduce blood pressure levels (8).
Moreover, an analysis of 29 human studies found that taking a vitamin C supplement reduced systolic blood pressure (the upper value) by 3.8 mmHg and diastolic blood pressure (the lower value) by 1.5 mmHg, on average, in healthy adults.
In adults with high blood pressure, vitamin C supplements reduced systolic blood pressure by 4.9 mmHg and diastolic blood pressure by 1.7 mmHg, on average (9).
While these results are promising, it's not clear whether the effects on blood pressure are long term. Moreover, people with high blood pressure should not rely on vitamin C alone for treatment.
SUMMARY
Vitamin C supplements have been found to lower blood pressure in both healthy adults and those with high blood pressure.
Heart disease is the leading cause of death worldwide (7).
Many factors increase the risk of heart disease, including high blood pressure, high triglyceride or LDL (bad) cholesterol levels, and low levels of HDL (good) cholesterol.
Vitamin C may help reduce these risk factors, which may reduce heart disease risk.
For example, an analysis of 9 studies with a combined 293,172 participants found that after 10 years, people who took at least 700 mg of vitamin C daily had a 25% lower risk of heart disease than those who did not take a vitamin C supplement (10).
Interestingly, another analysis of 15 studies found that consuming vitamin C from foods — not supplements — was linked to a lower risk of heart disease.
However, scientists were unsure whether people who consumed vitamin-C-rich foods also followed a healthier lifestyle than people who took a supplement. Thus, it remains unclear whether the differences were due to vitamin C or other aspects of their diet (11).
Another analysis of 13 studies looked at the effects of taking at least 500 mg of vitamin C daily on risk factors for heart disease, such as blood cholesterol and triglyceride levels.
The analysis found that taking a vitamin C supplement significantly reduced LDL (bad) cholesterol by approximately 7.9 mg/dL and blood triglycerides by 20.1 mg/dL (12).
In short, it seems that taking or consuming at least 500 mg of vitamin C daily may reduce the risk of heart disease. However, if you already consume a vitamin-C-rich diet, then supplements may not provide additional heart health benefits.
SUMMARY
Vitamin C supplements have been linked to a reduced risk of heart disease. These supplements may lower heart disease risk factors, including high blood levels of LDL (bad) cholesterol and triglycerides.
Gout is a type of arthritis that affects approximately 4% of American adults (13).
It's incredibly painful and involves inflammation of the joints, especially those of the big toes. People with gout experience swelling and sudden, severe attacks of pain (14).
Gout symptoms appear when there is too much uric acid in the blood. Uric acid is a waste product produced by the body. At high levels, it may crystallize and deposit in the joints.
Interestingly, several studies have shown that vitamin C may help reduce uric acid in the blood and, as a result, protect against gout attacks.
For example, a study including 1,387 men found that those who consumed the most vitamin C had significantly lower blood levels of uric acid than those who consumed the least (15).
Another study followed 46,994 healthy men over 20 years to determine whether vitamin C intake was linked to developing gout. It found that people who took a vitamin C supplement had a 44% lower gout risk (16).
Additionally, an analysis of 13 studies found that taking a vitamin C supplement over 30 days significantly reduced blood uric acid, compared with a placebo (17).
While there appears to be a strong link between vitamin C intake and uric acid levels, more studies on the effects of vitamin C on gout are needed.
SUMMARY
Vitamin-C-rich foods and supplements have been linked to reduced blood uric acid levels and lower risk of gout.
Iron is an important nutrient that has a variety of functions in the body. It's essential for making red blood cells and transporting oxygen throughout the body.
Vitamin C supplements can help improve the absorption of iron from the diet. Vitamin C assists in converting iron that is poorly absorbed, such as plant-based sources of iron, into a form that is easier to absorb (18).
This is especially useful for people on a meat-free diet, as meat is a major source of iron.
In fact, simply consuming 100 mg of vitamin C may improve iron absorption by 67% (19).
As a result, vitamin C may help reduce the risk of anemia among people prone to iron deficiency.
In one study, 65 children with mild iron deficiency anemia were given a vitamin C supplement. Researchers found that the supplement alone helped control their anemia (20).
If you have low iron levels, consuming more vitamin-C-rich foods or taking a vitamin C supplement may help improve your blood iron levels.
SUMMARY
Vitamin C can improve the absorption of iron that is poorly absorbed, such as iron from meat-free sources. It may also reduce the risk of iron deficiency.
One of the main reasons people take vitamin C supplements is to boost their immunity, as vitamin C is involved in many parts of the immune system.
First, vitamin C helps encourage the production of white blood cells known as lymphocytes and phagocytes, which help protect the body against infection (21).
Second, vitamin C helps these white blood cells function more effectively while protecting them from damage by potentially harmful molecules, such as free radicals.
Third, vitamin C is an essential part of the skin's defense system. It's actively transported to the skin, where it can act as an antioxidant and help strengthen the skin's barriers (22).
Studies have also shown that taking vitamin C may shorten wound healing time (23, 24).
What's more, low vitamin C levels have been linked to poor health outcomes.
For example, people who have pneumonia tend to have lower vitamin C levels, and vitamin C supplements have been shown to shorten the recovery time (25, 26).
SUMMARY
Vitamin C may boost immunity by helping white blood cells function more effectively, strengthening your skin's defense system, and helping wounds heal faster.
Dementia is a broad term used to describe symptoms of poor thinking and memory.
It affects over 35 million people worldwide and typically occurs among older adults (27).
Studies suggest that oxidative stress and inflammation near the brain, spine, and nerves (altogether known as the central nervous system) can increase the risk of dementia (28).
Vitamin C is a strong antioxidant. Low levels of this vitamin have been linked to an impaired ability to think and remember (29, 30).
Moreover, several studies have shown that people with dementia may have lower blood levels of vitamin C (31, 32).
Furthermore, high vitamin C intake from food or supplements has been shown to have a protective effect on thinking and memory as you age (33, 34, 35).
Vitamin C supplements may aid against conditions like dementia if you don't get enough vitamin C from your diet. However, additional human studies are needed to understand the effects of vitamin C supplements on nervous system health (36).
SUMMARY
Low vitamin C levels have been linked to an increased risk of memory and thinking disorders like dementia, while a high intake of vitamin C from foods and supplements has been shown to have a protective effect.
While vitamin C has many scientifically proven benefits, it also has many unfounded claims supported by either weak evidence or no evidence at all.
Here are some unproven claims about vitamin C:
Prevents the common cold. While vitamin C appears to reduce the severity of colds and recovery time by 8% in adults and 14% in children, it does not prevent them (37).
Reduces cancer risk. A handful of studies have linked vitamin C intake to a lower risk of several cancers. However, most studies have found that vitamin C does not affect the risk of developing cancer (38).
Protects against eye disease. Vitamin C has been linked to reduced risks of eye diseases like cataracts and age-related macular degeneration. However, vitamin C supplements have no effect or may even cause harm (39, 40, 41).
May treat lead toxicity. Although people with lead toxicity appear to have low vitamin C levels, there is no strong evidence from human studies that show vitamin C can treat lead toxicity (42).
SUMMARY
Although vitamin C has many proven benefits, it has not been shown to prevent the common cold, reduce cancer risk, protect against eye diseases, or treat lead toxicity.
Vitamin C is a water-soluble vitamin that must be obtained from the diet or supplements.
It has been linked to many impressive health benefits, such as boosting antioxidant levels, lowering blood pressure, protecting against gout attacks, improving iron absorption, boosting immunity, and reducing heart disease and dementia risk.
Overall, vitamin C supplements are a great and simple way to boost your vitamin C intake if you struggle to get enough from your diet.
From fresh strawberries to orange juice and multiflavored fruit snacks, children receive vitamin C from a number of sources. An antioxidant known for shortening the duration of the common cold, vitamin C helps the growth and maintenance of the body's tissues. Children need to eat foods filled with vitamin C because the body does not make the vitamin on its own. Thanks to stories of pirates who didn't have access to fruits and vegetables while at sea, scurvy is a well-known side effect of what happens when there's too little vitamin C in the diet, but few people know the effects of too much vitamin C.
Overdose is Possible, But Unlikely
While it's highly unlikely, a child can receive an overdose of vitamin C if she takes a "megadose" of a vitamin supplement that greatly exceeds the tolerable upper intake level for her age. An overdose can result in illness symptoms, but it is not toxic and does not require emergency care. In most cases, you do not have to worry about your child overdosing on vitamin C because the body does not store the vitamin. Even if your child receives a high dose of vitamin C through foods and juices and takes a supplement containing vitamin C, she will likely flush out the extra vitamin C when she urinates.
Recommended Dosing by Age
The Food and Nutrition Board at the Institute of Medicine sets recommendations for vitamins and minerals. For vitamin C, infants age 0 to 6 months need 40 milligrams a day, while infants 7 to 12 months need 50 milligrams a day. Children ages 1 to 3 years need 15 milligrams daily, those aged 4 to 8 need 25 milligrams daily, and children age 9 to 13 need 45 milligrams daily. For ages 14 to 18, girls should consume 65 milligrams each day, and boys should consume 75 milligrams each day.
Tolerable Upper Intake Levels
Unless your doctor has recommended a specific vitamin C dosage to combat scurvy after a severe vitamin C deficiency, a healthy child should not exceed the tolerable upper intake levels for his age. The UL is 400 milligrams a day for children age 1 to 3 years and 650 milligrams a day for children 4 to 8 years old. For children 9 to 13 years, the UL jumps to 1,200 milligrams a day. The UL is 1,000 milligrams per day for all adolescents aged 14 to 18. The U.S. Food and Nutrition Board of the institute of Medicine has not set tolerable upper intake levels for infants, as they should get all of their vitamin C through breastmilk, formula or food.
Vitamin C Complications
An overdose of vitamin C can cause complications that, for the most part, may make your child feel unwell and uncomfortable, but will not put him in serious harm. Overdose side effects include nausea, vomiting, diarrhea, heartburn, abdominal cramps, headache and insomnia. A vitamin C overdose can also increase the risk for kidney stones. Your child is more likely to be deficient in vitamin C than to consume too much, with side effects including a weakened immune system, slow wound healing, easy bruising, dry skin and hair, nosebleeds and bleeding and inflamed gums.
Whether in the form of a fizzy drink or flavored lozenges, cold and flu preventative supplements almost always highlight vitamin C as one of their key ingredients. So, what's so magical about vitamin C? Also known as ascorbic acid, vitamin C is critical to living healthily. Since the human body cannot spontaneously generate this nutrient, vitamin C must instead be absorbed from outside sources, such as vitamin supplements or foods that are naturally rich in it.
Commonly found in cold and flu preventative supplements, vitamin C strengthens and speeds up immune system functionality. Though research does not indicate that vitamin C intake alone can prevent the onset of cold or flu, adequate daily intake may shorten the duration of an infection or lessen the severity of symptoms.
Vitamin C is crucial for the maintenance of well being. For example, it plays a role in wound healing and helps maintain many essential body tissues. It also acts as a potent antioxidant and can repair damage from free radicals, which are linked to aging effects, and disease vulnerability. Additionally, vitamin C can also prevent anemia, since it helps the body increase absorption of dietary iron, another vital mineral that the body cannot spontaneously create.
Foods that contain high concentrations of vitamin C have been linked with a lower risk of cardiovascular disease, like heart attack and stroke. Vitamin C can also increase levels of nitric oxide, a compound that widens blood vessels and, in turn, lowers blood pressure. In addition, regular intake of vitamin C, along with other vitamins, has been linked to a decreased risk for developing age-related cataracts, a leading cause of visual impairment in the United States.
Common Sources of Vitamin C
Vitamin C can be easily obtained through the many different foods, including:
Citrus fruits and juices (orange, grapefruit, lemon, lime and tangerine)
Berries
Melons
Mangoes
Kiwi
Tomato
Broccoli
Red peppers
Spinach
Squash
Potatoes
Cooking these foods may result in the loss of some of the vitamin content, so it is ideal to ingest them raw, either whole or juiced. Nowadays, there are also numerous packaged food products, like cereals, that have been enriched and fortified with vitamin C, so that the nutrient can be easily obtained.
Vitamin C may also be labeled as "L-ascorbic acid" in supplement form, and most over-the-counter multivitamins contain the recommended daily amount of the vitamin. While it is a good source when an individual is in need of a vitamin C boost, supplements are not meant to replace a diet rich in naturally derived vitamin C.
What Happens When You Have Too Much — or Too Little — Vitamin C?
Vitamin C is a water-soluble vitamin that can be easily flushed out of the body via urination when it is not needed. Therefore, if the main source of vitamin C is from naturally occurring foods, it is near-impossible for excess vitamin C to produce side effects. However, taking excessive concentrated vitamin C supplements may lead to diarrhea or stomach upset.
Since vitamin C-rich foods are so readily available nowadays, symptoms of inadequate vitamin C intake are also rare in the United States. However, malnourished individuals can experience symptoms of vitamin C deficiency over time, including:
Weakness
Fatigue
Anemia
Easy bruising
Joint pain
Skin breakdown
Weakened tooth enamel
Gum inflammation
Severe vitamin C deficiency is referred to as scurvy. Scurvy can be easily treated with increased dietary or supplemental vitamin C. Since vitamin C is crucial in the detoxification of the body, a lack of vitamin C can compromise the immune system and make an individual more susceptible to diseases and infections. Individuals with insufficient vitamin C may find that it takes longer than usual to recover from a cold or a physical wound.
Daily Dosage Recommendations:
The daily dosage recommendation for vitamin C is different for everyone, depending on factors such as gender, age, lifestyle and current health condition. The recommended daily dosage for vitamin C is at least 75 mg daily for women and 90 mg for men. Since people who are pregnant, breast feeding, smoking or using oral contraceptives have a lower blood level of vitamin C than others, larger doses of vitamin C may be needed to achieve optimal results in these individuals. Those who have prior or current medical conditions may also require bigger or smaller dosage levels, as recommended by their healthcare providers.
Resource Links:
"Vitamin C" via MedlinePlus
"Vitamin C and Infections" via MDPI
"Extra Dose of Vitamin C Based on a Daily Supplementation Shortens the Common Cold: A Meta-Analysis of 9 Randomized Controlled Trials" via Hindawi, BioMed Research International
"Vitamin C" via National Institutes of Health
"Scurvy" via U.S. Department of Health & Human Services, National Institutes of Health
"Dietary intake and blood concentrations of antioxidants and the risk of cardiovascular disease, total cancer, and all-cause mortality: a systematic review and dose-response meta-analysis of prospective studies" via The American Journal of Clinical Nutrition
"Dietary vitamin and carotenoid intake and risk of age-related cataract" via The American Journal of Clinical Nutrition
"Cardiovascular System" via Department of Anatomy, Seoul National University College of Medicine (via Springer)
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