Life Extension Magazine

Life Extension Magazine August 2005

Report

Antioxidants

By Terri Mitchell

By Terri Mitchell

Antioxidants Reduce Mortality

Researchers in Belgium theorized that people have a certain balance of antioxidants and free radicals in their bodies, and if the balance were tipped toward free radicals, they would be more likely to die. So they came up with a scoreboard for oxidative balance in a group of smokers.30 Using diet as the basis, the smokers were divided into groups with low, medium, and high oxidative stress (which generates free radicals). Those with the highest iron intake and/or the lowest antioxidant vitamin intake had the worst score. At follow-up 10 years later, those with the worst score (based on high iron intake plus low beta-carotene and vitamin C intake) had a 44% higher risk of all-cause mortality and a 62% higher risk of cancer mortality than those with a good level of antioxidants.30

The study is confirmed by others showing that blood levels of antioxidants are “strongly predictive of mortality.”31 Lycopene and other carotenoids can slash the risk of mortality in half in nonsmokers.32 Antioxidant supplements and vitamin E can likewise reduce the risk of breast cancer recurrence,33 and lycopene can do the same in relation to oral cancers.34 Adequate levels of vitamin E, vitamin A, and lycopene are associated with a reduced risk of microangiopathy-related cerebral damage,35 and vitamins C and E taken as supplements at levels much higher than the US RDA can help protect against ovarian cancer.36 These findings are from just a few of the hundreds of published studies.

Different Radicals, Different Antioxidants

Of the several different types of free radicals, some are related to fat and others to water. Antioxidants that are great at scavenging one type of radical may have no effect on another. This was illustrated by researchers at the USDA’s Fruit Laboratory who studied different berries.37

The researchers found, for example, that juice from the “Hull Thornless” blackberry could inhibit four different types of radicals (hydroxyl, superoxide, singlet oxygen, and hydrogen peroxide) a lot better than vitamins E and C and all other berries tested. They discovered that beta-carotene is good at stopping singlet oxygen, but has no effect against hydrogen peroxide. Alpha tocopherol inhibited singlet oxygen radicals by 22.5%, better than strawberries at 15.41%.37

Not only does the type of berry make a difference, but whether it’s organic also counts. Researchers at the University of California at Davis found that organic frozen corn contains 50% more vitamin C than regular frozen corn, and that levels of phenolics were likewise higher in organic frozen strawberries.38

The Body’s Own Antioxidants

It’s not possible to avoid free radicals. Humans are bombarded with radical-generating radiation and toxins every day. On top of that, the body makes its own radicals. Energy production creates them and so does the immune system, where radical promoters such as hydrogen peroxide are synthesized inside cells and used to destroy invaders such as bacteria.

The body, however, has a remedy for its radicals: it creates its own antioxidants. Some of them are in the form of enzymes, which rely on metals such as selenium and zinc; these include glutathione peroxidase, superoxide dismutase, and catalase. Others are sulfur-related, and in-clude lipoic acid, N-acetylcysteine, and glutathione.

Cysteine, one of the sulfur-related antioxidants, is a critical component of glutathione, a major antioxidant for the liver, kidney, blood cells, and lungs, which are said to have an since they are exposed to both external and internal radicals.39 Prolonged or very intense oxidative stress can deplete glutathione and leave cells vulnerable to free radical damage. A quick route to glutathione depletion is drug and alcohol abuse.

Lipoic acid is another sulfur-related antioxidant synthesized in the body. It is unique because it can scavenge both water- and fat-type radicals, unlike most other antioxidants that go after one or the other. In a study of humans taking 600 mg of lipoic acid a day, three major areas of oxidative stress—LDL peroxidation, protein carbonyls, and isoprostanes—were reduced, a clear demonstration of lipoic acid’s multi-system activity.40 Lipoic acid is well known for its beneficial effects against diabetes, and has been used extensively in Germany and other countries to help manage diabetic neuropathy, protect the eyes, and more.41-43 Not only does lipoic acid help reverse the effects of diabetes, but Korean researchers recently demonstrated that the supplement can also help prevent diabetes from developing in the first place, at least in overweight rats.44

Glutathione levels decrease with age.45 Part of the problem occurs at the genetic level, where the genes that help manufacture it slow down.46 Supplemental lipoic acid not only can help reverse this loss and protect the heart and brain, but also can actually jump-start an aging gene into working again.45-47

Supplemental lipoic acid and L-carnitine are a powerful antidote to age-related antioxidant and energy loss. The two work synergistically in the body’s power plants known as mitochondria.48

Antioxidants and Chemotherapy

A study from the MD Anderson Cancer Center found that 62% of the patients at its clinics were taking herbs and/or vitamins,49 yet oncologists know little or nothing about how these supplements might affect conventional cancer treatment.

Chemotherapeutic drugs and radiation generate free radicals that damage both cancerous and healthy cells. It was previously thought that causing free radical damage to cancer cells was the principal way these treatments work. However, new research indicates that that’s not necessarily true. Some chemotherapies actually work better when free radicals are reduced.50 There is no definitive answer at the present time as to whether or not antioxidants should be taken during chemotherapy; it may depend on the type of cancer and type of drug being used.

Very few studies of antioxidants and chemotherapy have been done to date. Some confirm that antioxidants are beneficial during cancer treatment, while others indicate that some antioxidants may interfere with treatment. Still others show that certain antioxidants may enhance the cancer-killing effects of chemotherapeutic drugs.

As an example of the type of research that’s emerging, researchers at Columbia University report that children with acute lymphoblastic leukemia whose intakes of vitamin E, carotenoids, beta-carotene, and vitamin A are below the recommended daily allowance have more side effects from chemotherapy.51 In another study of women undergoing treatment for breast cancer, vitamin E or multivitamins helped maintain white blood cell counts (neutrophils), while folate had a negative impact on white cells.52

British researchers analyzed levels of selenium in people diagnosed with B-cell non-Hodgkin’s lymphoma.53 They found that if patients had high levels of selenium upon entering treatment, they had a better response, could tolerate higher doses, and were more likely to have long-term survival.

Italian researchers gave 300 mg of vitamin E a day to people undergoing chemotherapy with the drug cisplatin. When the vitamin was given prior to the drug and for three months after, toxicity to the brain was reduced from 85% to 30%. It’s not known whether a higher dose or different form of vitamin E might have slashed toxicity even further.54

Melatonin is well documented as a powerful antioxidant, particularly against radicals caused by radiation.55 In a study of people with metastatic non-small cell lung cancer, 20 mg of melatonin taken each night increased their ability to tolerate chemotherapy and achieve a better result. Three of 49 people were still alive at five years in the melatonin group, whereas none of the people in the group not receiving melatonin was still alive at two years.56

These and other studies are showing the effects of antioxidants in humans treated for cancer. Many animal studies already show beneficial effects for certain antioxidants used in conjunction with certain chemotherapies. But caution is warranted because some antioxidants can interfere with the ability of some chemotherapies to kill cancer cells.57