When this equilibrium is disrupted, it can lead to oxidative stress. Plants and animals, as well as all other forms of life, have their own defenses against free radicals and oxidative damage. Adequate antioxidant intake is important. In fact, your life depends on the intake of certain antioxidants — namely, vitamins C and E. However, many other non-essential antioxidants occur in food. The health benefits associated with a diet rich in plants is at least partially due to the variety of antioxidants they provide Berries, green tea , coffee, and dark chocolate are renowned for being good sources of antioxidants Meat products and fish also contain antioxidants, but to a lesser extent than fruits and vegetables 15 , Antioxidants can increase the shelf life of both natural and processed foods.
For instance, vitamin C is often added to processed foods to act as a preservative Your diet is an essential source of antioxidants, which are found in animal and plant foods — especially vegetables, fruits, and berries. Water-soluble antioxidants perform their actions in the fluid inside and outside cells, whereas fat-soluble ones act primarily in cell membranes. Notable examples include curcuminoids in turmeric and oleocanthal in extra virgin olive oil. These substances function as antioxidants but also have potent anti-inflammatory activity 19 , Some studies even show that high doses of antioxidants increase your risk of death 23 , For this reason, most health professionals advise people to avoid high-dose antioxidant supplements , although further studies are needed before solid conclusions can be reached.
Eating plenty of antioxidant-rich whole food is a much better idea. Many foods are good sources of antioxidants. The table below shows several types of antioxidants, their possible effects, and food sources of each. The big thing to notice is that antioxidants are found primarily in plant foods. The antioxidant minerals, selenium and manganese, are found in small quantities in meats and seafood, but the primary food source of all antioxidants is plant foods.
There is a huge range of antioxidant systems, and scientists haven't yet determined exactly how all the different systems work together in our bodies to protect us from free-radical damage. No one antioxidant can provide the protection offered by the many antioxidants working together. The best way to get a variety of antioxidants in the diet is to eat foods that represent all the colors of the rainbow. Each color provides its own unique antioxidant effects.
Bright orange, deep yellow fruits and vegetables like carrots, sweet potatoes, and apricots provide one type of antioxidant. Red foods like tomatoes, provide another. Green vegetables, such as broccoli and cabbage, and blue or purple foods, like blueberries and eggplant, each have their own antioxidant packages. Curcumin , the substance that makes turmeric yellow, is also believed to offer benefits.
Scientists began to theorize that free-radical damage was involved in the early stages of atherosclerosis and might play a role in the development of many other chronic medical conditions in the s. Studies at the time suggested that people who ate few antioxidant-rich fruits and vegetables had a greater risk of developing these medical conditions. So began several clinical trials in which antioxidant supplements like beta carotene and vitamin E were tested for their protection against heart disease, cancer, and other conditions.
As a result, "antioxidants" became a buzzword in the '90s, and their benefits were glorified by the media, by the the food industry who began labeling foods as "rich in antioxidants," and by the supplement industry as they began hyping the health benefits of antioxidant supplements. They were even promoted as anti-aging ingredients in beauty products. However, the research results were mixed and the anticipated benefits were not clearly present.
Vitamin C : Most fruits and vegetables, especially berries, oranges, and bell peppers. Vitamin E : Nuts and seeds, sunflower and other vegetable oils, and green, leafy vegetables. Beta-carotene : Brightly colored fruits and vegetables, such as carrots, peas, spinach, and mangoes.
Lutein : Green, leafy vegetables, corn, papaya , and oranges. Selenium : Rice, corn, wheat, and other whole grains, as well as nuts, eggs, cheese, and legumes. Goji berries and many other food products that contain antioxidants are available to purchase online.
The following foods are good sources of antioxidants. Click on each one to find out more about their health benefits and nutritional information:. Lycopene is the antioxidant that gives tomatoes their rich red color. When tomatoes are heat-treated, the lycopene becomes more bio-available easier for our bodies to process and use.
However, studies have shown that cauliflower, peas, and zucchini lose much of their antioxidant activity in the cooking process. Keep in mind that the important thing is eating a variety of antioxidant-rich foods, cooked and raw.
There is no set recommended daily allowance RDA for antioxidants, but a high intake of fresh plant-based produce is considered healthful. It is worth remembering that, while studies link the consumption of fruits and vegetables with better overall health, it is not clear whether how far this is due to the activity of antioxidants. In addition, caution is needed regarding supplements. A high intake of beta-carotene, for example, has been linked to an increased risk of lung cancer in smokers.
A high dose of vitamin E has been found to increase the risk of prostate cancer , and the use of some antioxidant supplements has been linked to a greater risk of tumor growth.
Antioxidant supplements may also interact with some medications. It is important to speak with a health provider before using any of these products. Under some circumstances, free radicals actually may be beneficial rather than harmful, and removing them may be undesirable. The antioxidant supplements may not have been given for a long enough time to prevent chronic diseases, such as cardiovascular diseases or cancer, which develop over decades.
The participants in the clinical trials discussed above were either members of the general population or people who were at high risk for particular diseases. They were not necessarily under increased oxidative stress.
Do not use antioxidant supplements to replace a healthy diet or conventional medical care, or as a reason to postpone seeing a health care provider about a medical problem. If you have age-related macular degeneration, consult your health care providers to determine whether supplements of the type used in the AREDS trial are appropriate for you.
If you are considering a dietary supplement , first get information on it from reliable sources. Keep in mind that dietary supplements may interact with medications or other supplements and may contain ingredients not listed on the label.
Your health care provider can advise you. Tell all of your health care providers about any complementary health approaches you use. Topics of recent NCCIH research on antioxidants include: The ways in which two chemical forms of vitamin E affect inflammation The biological effects of selenium on immune function The effects of a range of doses of alpha-lipoic acid on oxidative stress The effects of alpha-lipoic acid and acetyl-L-carnitine on inflammation in people with sickle cell disease.
Other components of NIH are also sponsoring research on antioxidants. For More Information. Toll-free in the U. MedlinePlus To provide resources that help answer health questions, MedlinePlus a service of the National Library of Medicine brings together authoritative information from the National Institutes of Health as well as other Government agencies and health-related organizations. Key References. Vitamin E and age-related cataract in a randomized trial of women.
Vitamin E and age-related macular degeneration in a randomized trial of women. Age-related cataract in a randomized trial of vitamins E and C in men. Archives of Ophthalmology. Estimation of antioxidant intakes from diet and supplements in U.
Journal of Nutrition. Archives of Internal Medicine. European Heart Journal. Clinical trials of antioxidants as cancer prevention agents: past, present, and future.
Dietary supplements and human health: for better or for worse? Vitamins C and E and beta carotene supplementation and cancer risk: a randomized controlled trial. Journal of the National Cancer Institute. Effect of selenium and vitamin E on risk of prostate cancer and other cancers.
Systematic review: generating evidence-based guidelines on the concurrent use of dietary antioxidants and chemotherapy or radiotherapy. Cancer Investigation.
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