Antioxidants are some of the most powerful protectors of your long-term health.
They work by protecting your body’s cells against damage from potentially destructive chemicals called free radicals. Free radicals can damage cells and materials such as DNA by oxidizing them in certain chemical reactions.
Antioxidants work against free radicals by neutralizing them so they can no longer oxidize and harm your body’s cells.
This article will examine the roles of the antioxidant vitamins A, C, D, E and K as well as Folic Acid.
An Introduction to Antioxidant Vitamins
Vitamins A, C, and E are the classic trio of antioxidant vitamins, but vitamins D and K and folic acid also increase antioxidant capacity in your body and make the antioxidant vitamins list.
You can get your antioxidant vitamins from food, but antioxidant supplements can help raise your levels further. In some cases, additional antioxidant vitamin supplements have already been linked to improvements in health or reductions in risk for certain chronic diseases related to oxidation.
Components of your diet that can have antioxidant activities or increase antioxidant powers in your body include vitamins, minerals, fatty acids, and a variety of phytonutrients, or plant nutrients.
In this article, we will have a closer look at the benefits, food sources and side effects of the antioxidant vitamins.
Vitamin A: Good for Your Eyes – and So Much More
One of the first nutrition facts you may remember learning is that carrots are good for your eyes. The reason is because of their high amount of vitamin A. Vitamin A is necessary for your vision; an early sign of deficiency is night blindness, or trouble seeing in dark places. This vitamin plays a role in the visual cycle which allows your eyes to send signals to your brain so your brain recognizes what you are looking at.
Vitamin A is a fat soluble vitamin that has more functions. It is necessary for lung, heart, eye, and ear development of fetuses and after birth. You need vitamin A for proper immune functioning and for healthy red blood cell production. Vitamin A can also act as an antioxidant.
Further Reading: What are the Benefits of Vitamin A?
The form of vitamin A you find in animal products is called pre-formed vitamin A, or retinol. This form is what your body uses most easily in the visual cycle and many other functions. Retinol can reduce damage to the fatty acids in your eyes by preventing their oxidation by free radicals.
Beta-carotene is the form of vitamin A you find in plant-based foods. It is a pigment, and it is what gives orange fruits and vegetables such as carrots, sweet potatoes, cantaloupe their color. This form of the vitamin is known as pro-vitamin A, since your body needs to process it to turn it into a more powerful form of vitamin A such as retinol. Beta-carotene has antioxidant activities, and higher intakes from fruits and vegetables may help lower risk of oxidative diseases such as heart disease, age-related macular degeneration, and cataracts.
Further Reading: What is Vitamin A?
Pre-formed vitamin A, or retinol, is in animal-based foods such as liver, cod liver oil, butter, and whole milk. Retinol is also the form in fortified foods such as some breakfast cereals and fortified milk.
Beta-carotene, or pro-vitamin A, is in orange fruits and vegetables including pumpkin, acorn squash, and mangoes, as well as leafy green vegetables such as kale and spinach.
Because of its fruit and vegetable sources, people who consume more beta-carotene are usually eating more healthy nutrients such as fiber and potassium.
Further Reading: Which are the Foods High in Vitamin A?
The jury is still out on whether antioxidant vitamin A supplements are beneficial for cancer and other diseases related to oxidation, but you can take supplements to boost your body’s levels. Beta-carotene is a good choice for an antioxidant supplement, since this form of the vitamin does not cause serious health risks.
Ask your doctor before taking any supplements, but be especially careful with vitamin A supplements in the form of retinyl palmitate or retinyl acetate, which are similar to preformed vitamin A in the form of retinol. Too much preformed vitamin A can cause hypervitaminosis A with symptoms including kidney, spleen, and liver, pain in your bones and joints, and weight loss.
Further Reading: Why Use Vitamin A Supplements?
Vitamin C: More May Be Better
Vitamin C is a water soluble vitamin. Not only is it vital in producing collagen which is used to protect your joints, vitamin C is the main antioxidant vitamin in your body’s tissues and blood. This vitamin is versatile. It protects a variety of molecules, including fats, proteins, and DNA, from free radicals that come from smoking, regular metabolism, and the environment.
Vitamin C may help lower your risk of heart disease, stroke, and high blood pressure. The National Cancer Institute notes that vitamin C can help slow the growth of certain cancers, including cancer of the pancreas, liver, colon, and prostate. Possibly because of its antioxidant effects, people who have adequate levels of vitamin C are less likely to develop Alzheimer’s disease and cataracts.
Further Reading: What are the Benefits of Vitamin C?
Getting plenty of vitamin C from your diet can be a sign that your diet is very healthy.
Except for a few rare exceptions, only fruits and vegetables naturally provide significant amounts of vitamin C.
Bell peppers are among the top sources among vegetables, with tomatoes, leafy green vegetables, and cauliflower also good sources.
Further Reading: Which Foods are High in Vitamin C?
As long as your doctor agrees in your particular case, vitamin C supplements are among the safest supplements to take.
They may have multiple benefits, such as lowering your risk of macular degeneration and heart disease even more than just getting vitamin C from food.
Extra benefits of vitamin C supplements include improving absorption of iron and fighting lead toxicity if you are exposed.
Further Reading: Why Use Vitamin C Supplements?
Vitamin E: Protecting the Cells of Your Body from Oxidation
Vitamin E is a fat-soluble vitamin whose main function in your body is as an antioxidant. Because it is fat soluble, vitamin E can access your cell membranes, which mostly comprise fatty acids and other fats, or lipids. Vitamin E can stop a potentially destructive series of oxidation reactions so the chain reaction does not continue and destroy large portions of your cell membranes.
Vitamin E has another very important antioxidant role. Since it is fat soluble, it can act on cholesterol, which is a type of lipid. Vitamin E helps prevent the oxidation of “bad” LDL cholesterol in your blood vessels. This is good news for your heart because LDL oxidation can lead to plaque formation in your arteries, atherosclerosis, and heart disease.
When a molecule of vitamin E works as an antioxidant to neutralize free radicals, it loses its ability to be an antioxidant. This is where vitamin C comes in to help. The presence of sufficient vitamin C allows vitamin E to regain its antioxidant function.
As an antioxidant, vitamin E is linked to a lower risk for certain age-related diseases caused by oxidation over a long period of time. As with vitamin C, for example, getting enough vitamin E may lower your risk of macular degeneration.
Your need for vitamin E increases as your intake of dietary fat increases. This is true even if you are relying mainly on “healthy” fats such as monounsaturated and omega-3 polyunsaturated fats.
The good news is that vitamin E is found in healthy high-fat foods.
Vegetable oils, olive oil, nuts, peanuts, and the germ portion of whole grains provide vitamin E. Green leafy vegetables are also good sources.
You’re not likely to have severe vitamin E deficiency unless you have fat malabsorption conditions, but supplementation can increase your vitamin E levels.
The best vitamin antioxidant supplement for vitamin E is the form called alpha-tocopherol.
While there are seven other forms of vitamin E – beta, gamma, and delta tocopherol along with alpha, beta, gamma, and delta tocotrienol – alpha tocopherol has the most antioxidant activity.
Vitamin D: An Undervalued Nutrient
Vitamin D may be best known for its role in bone health. Vitamin D is necessary for helping your body absorb and use the bone-building mineral calcium. It also affects your body’s use of phosphorus, which is another bone mineral. Without enough vitamin D, children’s bones will not mineralize properly as they grow. Adults with low vitamin D are at risk for osteoporosis and a high risk of bone fractures.
This vitamin is not “just” a bone nutrient. Vitamin D supports a strong immune system. Deficiency may raise your risk for autoimmune diseases including multiple sclerosis, lupus, and rheumatoid arthritis. In addition, vitamin D may lower your risk for heart disease and type 2 diabetes.
Vitamin D is also an antioxidant in the body, as recent research shows. In research published in the journal “Aging,” a team of researchers from New York Medical College and New Jersey Medical School looked at the effects of vitamin D on oxidative damage to DNA caused by free radicals. They found that adding vitamin D to the cells reduced the signs of free radical damage.
A study in “Ukranian Biochemical Journal” confirmed these effects. Researchers looked at liver cells, or hepatocytes, of mice with diabetes. They showed that in mice with vitamin D deficiency, there was less antioxidant activity and more oxidation in the cells. More liver cells also died in the vitamin D-deficient mice compared to their sufficient counterparts. It is possible that vitamin D in humans can protect liver cells.
In a different study published in the “International Journal of Preventive Medicine,” researchers from universities and medical schools in Iran supplemented pregnant women with calcium and vitamin D starting at week 25 of gestation. In 9 weeks, the women on average had a significant increase in total antioxidant capacity. This could theoretically lead to a decrease in oxidative-related diseases, such as cancer.
In fact, the antioxidant functions of vitamin D may be partly responsible for the link between adequate vitamin D levels and reduced risk of cancer. According to the National Cancer Institute, there is a link between low vitamin D levels and increased risk of colorectal cancer. There may also be a link to breast cancer.
Further Reading: Benefits and Functions of Vitamin D
Some people call vitamin D the “sunshine vitamin” because your skin can make it as a response to ultraviolet light from the sun. Younger adults who live in warm climates and get adequate skin exposure to the sun can make enough vitamin D without needing it from food or supplements.
On the other hand, older adults, people who wear concealing clothing that blocks the sun, people who use sunscreen most of the time, and people who live in northern climates are not always able to get enough vitamin D from sunlight.
Natural food sources of vitamin D include fatty fish such as salmon and herring, and egg yolks. However, vitamin D is not found naturally in many foods. You can get it from fortified milk, and other foods that are often fortified with vitamin D include almond and soy milk, orange juice, and breakfast cereals.
Further Reading: Foods High in Vitamin D
Since low vitamin D status is common, you might want to take a vitamin D supplement to get its full antioxidant effect. Vitamin D in the form of 1,25-dihydroxyvitamin D, or calcitriol or vitamin D2, may be an effective antioxidant vitamin form.
Vitamin D3, or cholecalciferol, is the form that is active in your body and also available as a supplement.
Further Reading: Why Use Vitamin D Supplements?
Vitamin K: Blood Clotting and More
Vitamin K is best known for its role in blood coagulation. In fact, vitamin K got its name from the “k” in “koagulation,” which is the German word for coagulation. However, vitamin K may be an important protector of your cells because of its antioxidant capacity.
The lipid, or fat-like, components of cells are some of the most common targets of free radicals because they are not very stable structures. Researchers from the University of Maastricht in The Netherlands looked at the effects of vitamin K on cell microsomes, which are floating structures within your cells. The results, published in the journal “Biochemical Pharmacology,” described a benefit of vitamin K in reducing oxidation of the lipid portions of microsomes.
You can get vitamin K from green vegetables, including Swiss chard, kale, spinach, and broccoli.
This fat soluble vitamin is also in healthy fats, such as soybean oil, olive oil, and cottonseed oil.
Consuming a source of fat with your source of vitamin K, such as adding salad dressing to your watercress salad, increases your absorption.
Outright vitamin K deficiency is rare in healthy adults because it is in so many foods, as well as because of your body’s ability to conserve it as needed. At the same time, antioxidant vitamin supplements can still increase your levels.
Vitamin K supplements can provide forms that are different from the form you might be most likely to consume from food. Leafy greens contain phylloquinone, while supplements can provide K2, or menaquinone, in amounts greater than the amount you will get from food. Menaquinone-4 (MK-4) and Menaquinone-7 (MK-7) supplements may have some benefits for bone and heart health.
Folic Acid: Not Just for Pregnant Women
Folic acid and folate are a B vitamin. Folate is the form of the vitamin found naturally in food, while folic acid is the form in fortified foods and in dietary supplements. The most common public health messages about folic acid are related to preventing neural tube birth defects, but folic acid is key in promoting heart health, assisting with vitamin B12 metabolism, and keeping your DNA safe.
Most people do not think of folic acid when they name antioxidants, but they may be overlooking an important antioxidant vitamin. According to a recent article in the Journal of the American College of Nutrition, folic acid supplements led to higher antioxidant capacity in men with type 2 diabetes. The study authors, who were researchers from Tabriz University of Medical Sciences in Iran, also found that vitamin B12 status improved, while certain markers of heart disease risk decreased.
Folate is naturally found in leafy green vegetables, which are known as “foliage” and actually give folate its name. Spinach and asparagus are good sources.
Orange juice and legumes such as lentils and garbanzo beans are also naturally rich in folate. By law, fortified grains must provide folic acid. You can take folic acid supplements to boost your levels.
One of the most popular roles of antioxidants is their potential to prevent cancer. As the National Cancer Institute explains, cancer can develop because of chemicals called free radicals and antioxidants work to neutralize these harmful chemicals.
Antioxidants have other likely benefits, too. They may lower your risk for diseases related to oxidation, including heart disease, cataracts, and macular degeneration. Oxidative stress is even related to aging, although scientists are still working on figuring out exactly how this works.
The roles of some antioxidant vitamins, such as vitamin A, vitamin C, and vitamin E, are well established, while the jury is still out on exactly how exactly other vitamins, such as vitamin D, vitamin K, and folic acid, function as antioxidants. Still, given the likelihood of their antioxidant functions and the importance of their other roles in the body, you are best off getting adequate amounts of these nutrients. If you cannot get them from food, or you need extra amounts, antioxidant vitamin supplements can boost your levels, and possibly your health.