Antioxidants Studies

As everyone knows, eating and drinking are necessary for life. Less well known, however, is the fact that the body generates what are called free radicals in the process of turning food into energy. Free radicals are chemicals that are capable of damaging cells and genetic material. But eating is not the only way free radicals spring into being. The food we eat and the sunlight we feel also generate free radicals.

To be sure, free radicals come in many shapes, sizes, and chemical configurations. The characteristic feature of this chemical is that it soaks up electrons from bodily substances that yield them, which can leave the “loser’s” structure or function radically altered. Free radical damage can change the instructions coded in a strand of DNA; it can also make a circulating low-density lipoprotein (LDL, sometimes called bad cholesterol) molecule more likely to get trapped in an artery wall. Free radicals also have the potential to alter a cell’s membrane, changing the flow of what enters the cell and what leaves it.

Fortunately, we aren’t defenseless against free radicals. The body puts up natural defenses against free radicals by making molecules that smothers the errant chemicals. We also extract free-radical fighters from food. Often called “antioxidants”, certain kinds of food give electrons to free-radicals without themselves turning into electron-scavenging substances. There are many different substances that can act as antioxidants. The most familiar ones are vitamin C, vitamin E, beta-carotene, and other related carotenoids, along with the minerals selenium and manganese. They’re joined by glutathione, coenzyme Q10, lipoic acid, flavonoids, phenols, polyphenols, phytoestrogens, and many more.

However, the term “antioxidant” can be misleading. These substances do not emit chemical properties that fight so much as they emit properties that facilitate. Indeed, some substances that act as antioxidants in one situation may be prooxidants—electron grabbers—in a different chemical milieu. Another big misconception is that antioxidants are interchangeable. This is not true. Each anti-oxidant has unique chemical behaviors and biological properties. It is believed, and has been strongly corroborated through scientific study, that anti-oxidants evolved as parts of elaborate networks, each substance having a different role to play. It follows that no single substance can fulfill the function of every other substance.

Health Benefits of Antioxidants: What’s the Buzz?

Antioxidants came to public attention in the 1990s. It was then that scientists began to understand that free radical damage was involved in the early stages of artery-clogging atherosclerosis, and that the chemicals may contribute to cancer, vision loss, and a host of other chronic conditions. A number of studies stated that people with low intakes of antioxidant-rich fruits and vegetables were at greater risk for developing these chronic conditions than were people who ate sufficient amounts fruits and vegetables. Clinical trials tested the impact of single substances, especially beta-carotene and vitamin E, on cancer, heart disease, and similar maladies. But even before the results of these trials were in, the media, and the dietary supplement and food industries began promoting the benefits of “antioxidants.” Foods such as frozen berries and green tea were hyped as being rich in antioxidants. The consequences of this publicity were predictable: certain foods were labeled as rich in antioxidants and were marketed as such in stores; the makers of dietary supplements began touting the disease-fighting properties of all sorts of antioxidants.

In the meantime, the results of the actual trials were mixed. Most have not found the hoped-for benefits. And research teams reported that vitamin E and other antioxidant supplements didn’t protect against heart disease or cancer. One study even showed that taking beta-carotene may actually increase the chances of developing lung cancer in smokers. However, some of the trials reported benefits. One such study found that taking beta-carotene is associated with a modest reduction in the rate of cognitive decline.

The rather most, if not downright disappointing, results of the antioxidant trials have not stopped the commercial interests from misrepresenting the benefits of antioxidants in order to make money. Antioxidant supplements are a $500 million dollar industry that continues to grow. Antioxidants are still added to breakfast cereals, sports bars, energy drinks, and other processed foods, and they are promoted as additives that can prevent heart disease, cancer, cataracts, memory loss, and a host of other conditions. The claims made by the food and dietary supplement industries often distort the data. It is true that the package of antioxidants, minerals, fiber, and other substances found naturally in fruits, vegetables, and whole grains help prevent a variety of chronic diseases; but there is no solid evidence that high doses of antioxidants can accomplish the same feat. The conclusion is clear: randomized, placebo-controlled trials—which, when performed well, provide the strongest evidence—offer little support that taking vitamin C, vitamin E, beta-carotene, or other single antioxidants provides substantial protection against heart disease, cancer, or other chronic conditions. The results of the largest such trials have been mostly negative.

Heart Disease and Antioxidants

Vitamin E, beta-carotene, and other so-called antioxidants are not a panacea for heart disease and should not be promoted as such. In the Women’s Health Study, 39,876 initially healthy women took 600 IU of natural source vitamin E or a placebo every other day for 10 years. The results of the study showed that the rates of major cardiovascular events and cancer were no lower among those taking vitamin E than they were among those taking the placebo; however, a 24 percent reduction in total cardiovascular mortality was observed, which can be considered a quite significant result.

Earlier large vitamin E trials, conducted among individuals with previously diagnosed coronary disease or at high risk for it, generally showed no benefit. In the Heart Outcomes Prevention Evaluation (HOPE) trial, the rates of major cardiovascular events were essentially the same in the vitamin E (21.5 percent) and placebo (20.6 percent) groups, although participants taking vitamin E had higher risks of heart failure and hospitalization for heart failure. (3) Another trial, the Gruppo Italiano per lo Studio della Sopravvivenza nell’Infarto Miocardico (GISSI), showed mixed results; there were no preventive effects after more than three years of treatment with vitamin E among 11,000 heart attack survivors. Nevertheless, some studies suggest potential benefits among certain subgroups. A recent trial of vitamin E in Israel, for example, showed a marked reduction in coronary heart disease among people with type 2 diabetes who have a common genetic predisposition for greater oxidative stress. In any case, Beta-carotene, as was shown in the Physicians’s Health Study, does not provide any protection against heart disease or stroke.

There have been combinations, but the findings are complicated and unclear. In the Supplementation en Vitamins et Mineraux Antioxydants (SU.VI.MAX) study, 13,017 French men and women took a single daily capsule that contained 120 milligrams of vitamin C, 30 milligrams of vitamin E, 6 milligrams of beta-carotene, 100 micrograms of selenium, and 20 milligrams of zinc, or a placebo, for seven and a half years. The vitamins had no effect on overall rates of cardiovascular disease. In the Women’s Antioxidant Cardiovascular Study, vitamin E, vitamin C, and/or beta-carotene had much the same effect as a placebo on myocardial infarction, stroke, coronary revascularization, or cardiovascular death, although there was a modest and significant benefit for vitamin E among women with existing cardiovascular disease.

Cancer and Antioxidants

There is also no conclusive proof that antioxidants help prevent cancer. Scientists need more time to determine the impact of antioxidants on the risk of getting cancer. In the long-term Physicians’ Health Study, cancer rates were similar among men taking beta-carotene and among those taking a placebo. Other trials have also largely showed no effect, including HOPE. The SU.VI.MAX trial showed a reduction in cancer risk and all-cause mortality among men taking an antioxidant cocktail but no apparent effect in women; it is possible that this is a result of the men in the study having low blood levels of beta-carotene at its beginning. A randomized trial of selenium in people with skin cancer demonstrated significant reductions in cancer and cancer mortality at various sites, including colon, lung, and prostate. The effects were strongest among those with low selenium levels at baseline.

Age-Related Eye Disease and Antioxidants

The effects of antioxidants on age-related eye disease may be one of the most hopeful leads scientists have. A six-year trial, the Age-Related Eye Disease Study (AREDS), found that a combination of vitamin C, vitamin E, beta-carotene, and zinc provided some protection against the development of advanced age-related macular degeneration in people who were at high risk of the disease. Lutein, a naturally occurring carotenoid found in green, leafy vegetables such as spinach and kale, may also protect vision. It is too early to tell what the impact of lutein supplements may be. The trials of such substances have been relatively short, and their ability to slow or prevent age-related macular degeneration has not been ascertained. A new trial of the AREDS supplement regimen plus lutein, zeaxanthin, and fish oil is underway, and it could yield better information.

Potential Hazards of Antioxidants

There have been a few studies which showed that the consumption of antioxidants, as opposed to being beneficial in all instances or at least harmless in fact can interfere with the health of the consumer. The first trial which showed this possible negative effect was undertaken in Finland where heavy smokers were fed beta-carotene. Because of their smoking habits there was a already a lung cancer risk but it was noticed that a significant increase in the incidence of lung cancer amongst the trial group as opposed to the placebo. The trial was stopped so conclusive results are hard to deduce.

A different test which was conducted with heavy smokers exposed to asbestos being fed beta-carotene and vitamin A. This too shows an increase in the incidence of Lung cancer. It must be emphasized that not all trials of Beta-carotene have been negative. A physicians health study which only had a few smokers did not show any significant differences even when followed up after 18 years.

In a separate study showing possible negative effects of a variety of health supplements showed a higher incidence of skin cancer in women being fed supplements of Vitamins C & E, Beta-carotene, selenium and zinc.

Conclusions to be drawn from the above studies, amongst others, is that it is known that although free radicals have been shown to contribute to the incidence of heart disease, cancer, Alzheimer’s and even vision loss, there is no automatic conclusion that can be drawn that antioxidants will fix the problem. And certainly not when consumed away from their normal context.

Studies to date do not show conclusive evidence one way or another but there is certainly no strong evidence to suggest that antioxidants are effective against disease. A rider must be mentioned and that is that the trials conducted till now have been short in duration, conducted with people some of whom had an existing disease.

There has been a noticeable benefit to the consumption of beta-carotene on cognitive ability after 18 years. This is exceptional as it is the only study to have continued so long. (Physicians health follow up study) Nevertheless there is abundant evidence suggests that eating whole fruits, vegetables, and whole grains—all rich in networks of antioxidants and their helper molecules—provides protection against many of these scourges of aging.

Clarification with regard to supplemental studies

There are any number of studies conducted on any number of vitamins and other dietary supplements that are often contradictory. The picture presented to the consumer is confusing and will often seem frustrating in that instead of clarifying things these studies muddy the waters.

Examining exactly what the vitamins trial study did will often go some way to explaining the varying results. Here are a few items to check when looking at apparently conflicting vitamins studies.

  • What was the precise dosage taken by the participants and how long was the study’s duration. This is significant as few studies will have identical dosages and identical time spans. A study in Vitamin D showed that a dosage of 700 plus IU per day had a significant protection against fractures whereas a study of people taking only 400 IU per day showed no such effect. The same applies to the duration as the build up of the protective mechanisms is not a short process.
  • The age, health and life styles of the participants. Studies drawn from young, active gym going participants is likely to differ significantly from heavy drink and smoking office workers. Exercise and other lifestyle choices such as diet affect out health and how the body responds to vitamins.
  • At what stage is was the supplement fed to a study participant. If studying the effect of a supplement on someone already suffering from a disease it may be found that something taken at the onset has a differing effect from something taken when a disease is far advanced. An example being that Folate supplements are only effective against neural tube defects in the early stages of pregnancy.
  • How were the results tabulated and calculated. This is a significant problem as measurement as to benefit may and probably will vary widely. Heart disease is a wide subject and a measurement of coronary thrombosis may miss out on the incidence of strokes.

Polycystic Ovary Syndrome (PCOS)

Every month, follicles grow on a woman’s ovaries. When the follicles don’t develop properly they can form cysts on the ovaries’ surfaces, which, when accompanied by hormonal imbalance, can lead to PCOS.

In a normal cycle, several follicles develop on the surfaces of your ovaries. In one of those follicles, a single egg matures more quickly than the eggs in the others, and is released into the Fallopian tube. All the remaining follicles then die away. If you have polycystic ovaries, you have a number of undeveloped follicles remaining on the surfaces of your ovaries, making the ovaries appear enlarged. In itself, this isn’t necessarily a problem – many women have polycystic ovaries and have regular cycles and no problems getting pregnant. However, if you also have higher-than-normal levels of certain sex hormones, such as androgens (“male” hormones, including testosterone) and luteinizing hormone (LH), you have polycystic ovary syndrome, a condition that triggers symptoms such as irregular or absent periods, excess hair, and weight gain.


The causes of PCOS continue to perplex even the experts who specialize in it. Although there’s a strong genetic and hereditary link for the condition, many problems stem from the simple fact that the ovaries can’t seem to produce hormones in the correct proportions. The pituitary gland then gets the message that the ovaries aren’t working properly and releases more LH. Women with PCOS often have problems with blood-sugar swings, which cause the pancreas to release more insulin, which in turn targets the ovaries to produce more testosterone. The adrenal glands and liver are then affected, producing more male hormones in your system. All in all, you’re in a vicious cycle.


If you suspect that you have PCOS, it’s important you see your doctor as soon as possible, as early diagnosis can help prevent long-term complications of the condition, such as infertility and diabetes. If, after performing the following tests, your doctor confirms diagnosis of PCOS, you may be referred to a specialist in endocrinology (hormones) or to a gynecologist.

Ultrasound Your doctor may decide to give you an ultrasound scan, which he or she will use to establish whether or not there are undeveloped follicles that remain on the surfaces of your ovaries.

Blood tests Your doctor will perform a blood test to check levels of follicle-stimulating hormone (FSH) and LH, androgens (male hormones), and SHBG (sex-hormone-binding globulin). High levels of LH and/or androgens, and/or low levels of SHGB can indicate a problem. Note that you don’t’ have to have all these hormone imbalance to have PCOS, just one of them, plus the polycystic ovaries that showed on an ultrasound.

Conventional Treatments

There’s no question that it’s crucial to manage PCOS. Your doctor will probably offer you the following conventional treatments.

Hormone treatments As PCOS is essentially a problem with the balance of hormones in your body, it stands to reason that your doctor will offer you some medication to regulate your body’s hormone production. The standard treatment for women who aren’t planning to have a baby is the anti-testosterone contraceptive pill. This drug can help eliminate some of the more “male” symptoms of PCOS, such as acne and excess hair, but it doesn’t treat the cause.

If you’re aiming to get pregnant, your doctor may offer you clomiphene citrate. Most women find that this stimulates ovulation, but it can also hamper your ability to carry your baby to term. Use clomiphene for a maximum of six months. If it’s unsuccessful, your doctor may try medications such as gonadotrophins.

Insulin sensitizers The link between PCOS and insulin resistance means that some doctors prescribe type II diabetes medication to treat PCOS, too. You’ll most likely be offered metformin. For some women, metformin doesn’t work at all; while several studies show that it increases the efficacy of clomiphene, so you may be prescribed both medications. A powerful drug, metformin causes stomach upsets in up to a fifth of the women who take it.

Surgery As a last resort, your doctor may advise a laparoscopic ovarian diathermy, also known as ovarian drilling. The procedure causes your levels of testosterone to fall in the hope that this will stimulate your ovary to release an egg. Although surgery works in the short term, it’s likely the PCOS will return, which is why doctors use it only when all other treatments have failed.

Your Diet

There is overwhelming evidence to suggest that diet plays a significant role in the natural management of PCOS. Therefore, before you go on any medication for the condition, try the nutritional approach to managing it. Follow the nutritional recommendations below for six months (including taking the supplements). If, after this time, you see no signs of improvement (for example, if your hair growth hasn’t slowed down, if your periods aren’t more regular, and so on), go back to your doctor.

If you’re overweight, it’s crucial that you bring your weight down to the appropriate level for your height. Being overweight increases insulin levels dramatically and makes the symptoms of PCOS worse. Losing weight, on the other hand, results in lower insulin levels, which in turn reduce the testosterone levels that are interfering with ovulation. So follow the hormone-balancing diet and increase the amount of exercise you get. Aim to get your BMI in the right range for your age and height.

Adapting your eating habits so you keep your blood sugar levels on an even keel throughout the day is an essential component of the natural approach to treating PCOS. If your adrenal glands are over-stimulated by ever-fluctuating sugar highs and lows, they produce too much adrenaline – the stress hormone – and also too much androgen (male hormone), preventing ovulation altogether. Although in the West, we tend to base our day around “three square meals”, this isn’t the best way to eat if you suffer from PCOS. Try six smaller, well-balanced meals (ideally comprising low-GI foods) a day, instead.

Phytoestrogens Eating foods, such as soy, chickpeas, and lentils, that contain natural estrogens can be beneficial for women with PCOS because phytoestrogens help control levels of testosterone in the blood.

Pregnancy and PCOS

Many women with PCOS can achieve pregnancy following the natural approach. However, never stop taking any prescribed medication without letting your doctor know first and asking for his or her support.

If you’re under 35 Once you stop taking your medication, give your body six months using all the natural advice from the experts. Then stop taking the co-enzyme Q10 and the herbs and start trying for a baby.

If you’re over 35 Follow your doctor’s advice about which medications to take. On top of this, take a reputable multi-vitamin and mineral supplement and follow all nutritional advice from the experts in the industry. DO NOT take the herbs or co-enzyme Q10.

Non-Nutrient Substances in Foods

There are a whole range of biologically active substances in foods, especially plant foods and herbal remedies, apart from those accepted as nutrients. Some of these are harmful or affect the availability of nutrients in the diet, but others may have beneficial effects on health. Many of the active substances have been isolated and are now available as dietary supplements; however, their presence, previously unrecognized, is probably the best advertisement there is for eating a varied diet, including plenty of vegetables, pulses, and fruits, s it is quite possible that there are still other substances that remain to be discovered. Much of the evidence for the benefit of such substances ahs come from epidemiological studies, where the prevalence of certain types of disease is related to the consumption of specific foods or food groups within the community. Further scientific study is then needed to identify the particular active component and demonstrate an effect in the body. The following outline the importance of some of the compounds that have been studied more extensively.


Oxidation is an essential process whereby the nutrients we obtain from foods are oxidized in a controlled manner involving the consumption of oxygen. Carried out at a cellular level, oxidation releases energy for metabolism and transformation of nutrients into body tissue and generation of heat. The oxygen is ultimately converted into water and excreted. However, during this process so-called free radicals or reactive oxygen species are formed that, unless mopped up by the body’s antioxidant defences, can damage the tissues, increasing the rate at which they age and potentially contributing to a range of degenerative diseases such as arthritis, immune disorders, cancer, stroke, coronary heart disease, and many others. Antioxidants are substances produced by the body, or consumed in foods, that significantly delay or prevent the oxidation of a particular substrate.

Some vitamins and trace elements in the diet contribute to the body’s antioxidant arsenal. Vitamins A (as beta-carotene), C, and E are known as the antioxidant vitamins, and selenium, copper, manganese, and zinc are components of antioxidant enzymes. In fact the carotenoids, the red-orange pigments in plants, comprise about 600 different substances, of which about 60 are precursors of vitamin A. Many of the non-provitamin carotenoids, including substances such as lycopene, zeaxanthin, and lutein act as antioxidants. Lycopene is the most interesting of these. It is present in tomatoes and, therefore, in food products such as ketchup and sauces. Cooking releases the lycopene and makes it more available, especially in the presence of a small amount of oil or fat. Recent epidemiological studies have suggested that consumption of tomatoes and products containing them is associated with a lower incidence of prostate cancer. Consumption of 10 or more servings per week of foods containing tomatoes, including soup, pizza, and pasta sauces afforded the greatest protection. In addition, non-nutrients such as phytoestrogens, flavonoids, phenolic acids, and polyphenols such as tannins are present in foods and drinks, and may help to prevent oxidation in the plant as well as in human tissues.


Flavonoids are phenolic compounds that are water soluble and occur widely in nature. There are hundreds of different flavonoids found in fruits, vegetables, and beverages such as tea and wine. The particular flavonoids in tea and wine have strong antioxidant effects. Epidemiological studies have suggested that the risk of coronary heart disease is substantially lower in people within populations with the highest flavonoid intake, possibly due to the prevention of oxidation of low-density lipoproteins and reducing blood clotting. The most widely distributed flavonoid in foods is quercitin, followed by kaempferol, but others include myrecitin, catechin, apeginin, and luteolin. In a Dutch study investigating flavonoid intakes, black tea was found to supply more than half the intake, followed by onions and apples.


Phytoestrogens are steroid substances derived from plants, that, it has been suggested, have several potentially beneficial actions in the body. Epidemiological studies suggest that in populations where there is a high intake of phytoestrogens the incidence of certain cancers, especially hormone-sensitive types such as some forms of breast cancer and ovarian cancer in women and prostate cancer in men, is lower. One group, known as lignans, are derived from the bacterial digestion of polyphenols, and many oilseeds such as soya bean, rapeseed, and flax are rich sources of the lignans or their precursors. Women in countries with high consumption of soya beans and soya products have been shown to have a lower incidence of breast cancer. This may be related to the phytoestrogen content of the foods as well as to the presence of flavonoids and other phenolic compounds. Soya is also a rich source of another class of phytoestrogens – the isoflavonoids – especially diadzein and genistein.

Phytoestrogens appear to increase the binding of sex hormones to the protein on which they are carried in the blood, thus resulting in lower levels of biologically active free hormone, but they also have other potentially beneficial effects. Some have antioxidant effects that are cancer-preventing, while others appear to reduce the proliferation of cells that respond to oestrogens (such as in the breast and uterus) either by inhibiting enzymes involved in cell proliferation or by competing with oestrogens for binding sites. Food manufacturers are taking the opportunity to make products in which the above potentially beneficial components of foods are concentrated naturally, or are adding tem to other foods. For example, soya, flax, and linseed may be added to breads to increase the phytoestrogen content, with the breads then being advertised as functional foods.

Phytoestrogens are also regarded as active principles in herbal remedies.

Functional Foods

These are foods that appear to have health benefits beyond the provision of nutrients and energy. A symposium on the topic gave the following definition “a food can be said to be functional if it contains a compound, which may or may not be a nutrient, that affects one or a limited number of functions in the body in a targeted way so as to have positive effects on health”. The health benefits may be physiological or may take the form of a positive psychological effect.

Functional foods may be foods that contain the beneficial substance naturally, e.g. fruits and vegetables contain a variety of antioxidant substances that are not strictly nutrients but have beneficial effect: wholegrain cereals contain dietary fiber that may have beneficial effects on gut function and help prevent heart disease: soy beans contain phytoestrogens that may have beneficial effects as described above. However, increasingly food manufacturers are producing foodstuffs with ‘functional” added ingredients that may be of benefit to health. For example, spreads with plant sterols or plant stanols added may help lower cholesterol levels; addition of specific bacteria, called probiotics, to yoghurts and yoghurt drinks, may have beneficial effects within the gut and beyond; and chewing gum containing phosphatidylcholine is claimed to improve memory.