Antioxidants are necessary to protect your body from free radical damage. Here are some of the main ones, including food sources.
A polyphenolic compound.
Source – grape skins, cranberries, blueberries, peanuts, knotweed. The amount in grapes (and therefore red wine) varies depending on the climate that the grapes were grown in and their exposure to fungal infection – resveratrol is produced by the grapes as a natural defense against fungal attack.
Red wines around the world only contain around 0.2-0.7mg per standard 100ml drink – therefore 1-2 glasses of red wine only provides 0.2-1.4mg resveratrol.
There is no RDA yet for resveratrol, but a generally accepted therapeutic dose is 300mg per day. It is not practical to get this amount from red wine as you would need to consume 5-17 dozen bottles per day – you would be dead from alcohol poisoning very quickly!
Scientific studies have shown resveratrol to help to prevent cancer and it also has anti-tumour and anti-metastatic activity. Other scientific studies have shown resveratrol to protect the heart from damage and to be anti-inflammatory. In clinic, I have also seen a therapeutic dose of resveratrol in combination with some other antioxidants to have an anti-ageing effect on skin, reducing wrinkles and making skin look younger.
As yet, there are no known deficiency states from not consuming enough resveratrol (hence no RDA) however as it can help protect against cancer and heart disease I think it is worth adding as a supplement if your personal or family history indicates it.
One of the problems of trying to get your resveratrol from red wine is that as little as one alcoholic drink per week has been shown to increase the risk of several cancers, including breast cancer.
There are some studies that show that resveratrol can induce the BRCA genes, so if you carry these genes this might not be the best thing for you to consume.
A fat-soluble vitamin. May be measured in retinol equivalents. Beta carotene is a pre-cursor to vitamin A.
Food sources include: grilled lamb liver 33,337mcg/100g portion; chicken liver pate 9,948mcg/100g; raw peeled mature carrot 1,316mcg/100g or carrot juice 1,780mcg/100ml; baked orange sweet potato 1,239mcg/100g; raw green basil, 528mcg/100g; raw curly parsley 827mcg/100g. Most pumpkins, when baked, contain around 500-600mcg/100g – interestingly, however, Jarrahdale pumpkin misses out and only has around 81mcg/100g.
The RDI for an adult in Australia is 700-900mcg (2,333-3,000iu) retinol equivalents per day, with a recommended upper limit of around 3,000mcg (10,000iu) retinol equivalents per day. Pregnancy and lactation call for higher amounts – 800-3,000mcg per day during pregnancy and 1,100-3,000mcg per day during lactation. To get this from your food is really easy – eat a couple of carrots or 100g of baked orange sweet potato, or drink 200ml carrot juice with some basil or parsley mixed in every day – the trick is, because it is a fat-soluble vitamin, you need to have some good fats or oils at the same time – so drizzle a bit of olive oil on your carrots and sweet potato, and have an avocado or some nuts with your carrot juice. Caution is advised when consuming liver in any form – don’t have too much and don’t have it regularly – you can die from vitamin A poisoning from eating too much liver (as happened to polar explorers when they polar bear or sled dog liver, not wanting to waste any of the animal they had had to kill for food).
Vitamin A is needed for eye health including night vision, and for a healthy immune system. You need vitamin A for growth and development. It also helps you to have healthy skin. A severe deficiency can cause blindness.
Vitamin A is essential during pregnancy to prevent birth defects. Yes, really. In the same way that too much vitamin A during pregnancy causes birth defects, so does not enough. The type of birth defects seen from gross vitamin A deficiency during pregnancy include cleft palates and babies born with no eyes.
Vitamin A is depleted by alcohol consumption and smoking. Because it is fat-soluble you need to consume fats or oils at the same time as the vitamin A to be able to absorb it. Vitamin A is stored in the liver and requires adequate levels of zinc consumption to be mobilized out of storage for the body to use.
A water-soluble vitamin.
Best food sources include: blackcurrant juice 180mg/100ml, raw guava 243mg/100g, raw red capsicum 152mg/100g, raw strawberry 45mg/100g, fresh boiled broccoli 57mg/100g, raw cherry tomato 28mg/100g, raw peeled papaya 60mg/100g, ground cinnamon 29mg/100g. raw green basil 53mg/100g. A typical raw peeled orange only has 44-57mg/100g.
The RDI for vitamin C in Australia is very low – 45mg per day for an adult – this is the amount you need to prevent gross deficiency diseases such as scurvy. There is no upper limit. If you take too much vitamin C in supplement form the short term adverse effect will be diarrhoea but this will settle quickly once you reduce the dosage. I think that for general good health effects a sensible daily amount would be 200-1,000mg per day.
Vitamin C is essential for very many functions in the body – it is needed for a strong immune system (and has been shown to reduce the duration and severity of the common cold), skin and connective tissue, eye health, respiratory function/healthy lungs, it can help protect against cancer, it has anti-inflammatory effects and it helps protect your heart. Vitamin C is needed for the absorption of iron and helps to protect vitamin A and vitamin E. Deficiency symptoms you may notice include easy bruising, bleeding gums when you brush your teeth, slow wound healing, stretch marks, iron-deficiency anaemia, elevated blood pressure, and cataracts. Vitamin C can help protect your gut from ulcerating if you are taking aspirin.
Vitamin C is depleted by the oral contraceptive and hormone replacement therapy, smoking, and stress.
Don’t take vitamin C supplements if you have haemochromatosis as vitamin C increases iron absorption and haemochromatosis is a genetic disease causing iron overload in the body.
Another fat-soluble vitamin, you might see this called tocopherols – there are several but the most commonly found in supplements is alpha tocopherol (?-tocopherol). The best form of this is called d-?-tocopherol. Cheap supplements will have it as dl-?-tocopherol, but the l-form does not work so you are only getting half the dose you think you are. You may see it measured in mg (milligrams) or iu (international units).
Best food sources are: tahini 213.57mg/100g, almonds with the skin on 28.14mg/100g, olive oil 19.94mg/100ml, raw hazelnuts 16mg/100g, boiled whole chicken egg 12.86mg/100g, wheatgerm 11.96mg/100g.
Current RDI for vitamin E for an adult is 7-10mg (7.8-11.11iu) per day, increasing to 11-12mg (12.2-13.34iu) per day in lactation; the recommended upper limit is 250-300mg (278-333.34iu) per day.
Vitamin E helps to protect your heart, cell membranes, and is protective against cancers including prostate cancer. A deficiency would lead to an increased risk for heart disease, cancer, and premature ageing.
Vitamin E increases the effects of warfarin – this needs to be monitored by your doctor.
This is an essential mineral. It is an essential component of glutathione peroxidase which is the main antioxidant inside your cells.
Best food sources include: Brazil nuts 920mcg/100g, steamed yelloweye mullet 116.4mcg/100g, simmered lamb kidney 144.2mcg/100g, roasted lean pork loin 38.5mcg/100g, steamed blue mussels 95mcg/100g, steamed green mussels 67.2mcg/100g, raw oysters 69.4mcg/100g, grilled lean chicken breast 34.6mcg/100g, casseroled rabbit flesh 37mcg/100g, whole boiled chicken eggs 38.8mcg/100g, grilled lean lamb chump chop 30mcg/100g, garlic 25mcg/100g.
The RDI for an adult in Australia is 60-70mcg per day (75mcg per day during lactation), with a recommended upper limit of 400mcg per day.
Selenium helps to regulate thyroid function, it protects vitamin E, it helps to prevent fatty liver, and it protects against cancer and heart disease. Selenium helps to prevent gene mutations in your DNA. Selenium also helps to regulate cholesterol, insulin, and blood pressure. Scientific studies have shown that all study participants who had cancer were deficient in selenium and zinc. If you are low in selenium you are at increased risk for cancer, heart disease, cataracts, liver disease, infertility, skin problems including dandruff, and thyroid disease. As your body only stores selenium for the short term, it is important to consume it regularly. Selenium helps to protect your body from the effects of mercury and cadmium.
Low protein intake tends to reduce absorption of selenium.
Selenium starts to become toxic when taken in extremely high doses where there is no known deficiency pre-existing. High-dose supplementation must not be undertaken without the supervision of an appropriately qualified health practitioner. Selenium toxicity is more common from industrial exposure and if not corrected it will lead to death. High amounts of garlic consumption (more than 2 cloves per day) interacts with warfarin and other blood-thinning medications, increasing their effect.
Zinc is an essential mineral and is very commonly deficient throughout the population. Zinc is an essential component of the antioxidant superoxide dismutase.
Best food sources are: raw oysters 47.89mg/100g, grilled lean beef medallion 8.2mg/100g, lean grilled lamb chump chop 5.8mg/100g, raw cashew nuts 5.5mg/100g, hulled & dried pumpkin seeds 7.46mg/100g, tahini 5.53mg/100g, grated parmesan cheese 6.5mg/100g. The phytates in plant foods (such as grains and vegetables) block zinc’s absorption so grains are not a useful source.
The RDA in Australia is ridiculously low at 8-14mg per day for an adult with a recommended upper limit of 40mg per day. A recommended useful amount would be 20-50mg per day for an adult. To get this from your food, you would need 100g of oysters daily, or 400-500g grilled lean beef daily, or for the vegetarians 600g of pumpkin seeds or 700g raw cashews daily (caution – this amount is not realistic and is likely to cause nausea and diarrhoea due to the fat content and in the long term this high consumption of cashew nuts would lead to obesity due to the high carbohydrate content).
You need zinc for a happy and healthy mood, to be able to digest your food, for all aspects of fertility and reproduction, for blood sugar regulation, blood pressure regulation, immune system function including antiviral activity, skin health, eye health, healthy bones and teeth, kidney function, liver function, connective tissue, to be able to absorb folate and other vitamins, to be able to mobilise vitamin A from liver stores, and for normal growth. Zinc is an essential component of the antioxidant superoxide dismutase. Zinc helps to prevent and treat many diseases including cancer. It is necessary for hormone regulation, wound healing, vision, taste, smell, appetite, energy, detoxification of chemicals including alcohol, and to protect the prostate. Zinc is anti-inflammatory.
Correct zinc supplementation can help to prevent many side-effects of cancer treatment (but this is not something to try to do on your own!).
If you don’t get enough zinc, eventually you will die. Deficiency symptoms you would notice include acne, PMS, mood swings, indigestion/reflux, poor appetite (you are not hungry in the morning, you only eat because you know you should or because you feel faint), stretch marks, depression, poor sense of taste & smell, diarrhoea, all types of mental illness, autism, behavioural disorders such as ADHD, low libido, problems getting pregnant or maintaining a pregnancy to full term, colds and ‘flu that hang around and don’t want to go away. You might be craving earth, clay, or salt. Anorexia has been linked to zinc deficiency.
Alcohol and smoking reduce absorption and increase excretion of zinc from the body. Needs are increased if you use oral contraceptives, cortisone/steroids, and diuretics. Needs are also increased during times of growth such as puberty, pregnancy, etc.
Zinc tablets come with a government warning that it is dangerous when taken in excess. This is why I seldom prescribe it in tablets – there are practitioner-prescribed products that come in a liquid or powder form that are difficult to overdose on as if you take too much at once you will vomit it back up (this does not happen with tablets).
Lycopene is an antioxidant carotenoid found in red vegetables and fruits, with its highest known concentrations in common tomatoes with 537.5mcg/100g – cooking increases the bioavailability. There is no established RDI yet.
Recommended intakes vary between 2-30mg per day – this would require eating at least 400g of cooked tomatoes daily. Maybe a couple of glasses of tomato juice might be an easier way to take it.
Lycopene has been found to help prevent cancers, heart disease and stroke.
Lutein is another antioxidant carotenoid.
Main food sources are: boiled frozen green peas 620mcg/100g, cooked fresh broccoli 352.5mcg/100g, hardboiled or poached whole chicken egg 342mcg/100g.
There is no RDI yet for lutein. About 6-14mg per day appears to be the dose needed to correct vision problems such as tired eyes and macular degeneration. The body cannot make its own lutein so it must be eaten regularly. A deficiency would eventually lead to blindness.
Epigallocatechin gallate (EGCG)
This is the antioxidant component of green tea and also comes in supplement form (made from green tea).
There is no RDI for EGCG. Health benefits are usually thought to require 5-6 cups of green tea per day.
EGCGs have been shown in scientific studies to be beneficial against cancer, acne, obesity (helping with fat burning in higher doses), and potentially beneficial for arthritis and other degenerative diseases.
Be aware that green tea does contain about 30mg of caffeine so high intakes of green tea may lead to caffeine side-effects in sensitive individuals. Of course, a cup of green tea has far less caffeine than a cup of coffee.
CoQ10 (also called coenzyme Q10 or ubidecarenone or ubiquinone)
CoQ10 is found throughout the body and is essential for heart health and energy production in the mitochondria.
There is currently no RDI for CoQ10. It is generally agreed that 75-300mg per day is the required therapeutic amount.
CoQ10 rejuvenates other antioxidants such as vitamin E, offers protection from free radical damage in the cells, helps the mitochondria make energy, and protects your heart. It can be helpful in cancer patients, and it helps to boost the immune system.
Lack of CoQ10 can lead to heart attack and congestive heart failure. Low levels of CoQ10 have been found in patients with fibromyalgia and supplementation relieved their symptoms. CoQ10 is also beneficial in chronic fatigue to aid energy production.
Beta-blockers (a type of blood pressure medication) and statins (cholesterol tablets) actually block your body’s own natural production of CoQ10. In the long term, this means that these drugs actually increase your risk of suffering a heart attack or heart failure and make you fatigued. Oral contraceptive and hormone replacement therapy also significantly lowers levels of CoQ10 in your body. If you take these drugs you must also take a CoQ10 supplement to reduce this risk.
There are no known adverse effects, however it may interact with warfarin – this needs to be monitored by your doctor.
For more information on antioxidants, including which ones you need and what products you should take, book your appointment with Kathy now.
Kathy Cooper AdvDipNutMed, DipNut, DRef, DRM, DSpTh, NFMC, C.Irid, C.Astro, MATMS