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.

What are antioxidants and what do they do?

That’s a very good question. They are both natural substances and synthetic substances that help treat free radicals in the body. Free radicals are a natural byproduct of some cellular metabolism. They’re useful for the immune system for killing foreign cells and bacteria; but if the situation gets out of control, they can be harmful to the body. A free radical is a substance that has lost an electron and is therefore an unstable ion. What it wants to do is become stable again. So it attacks a cell that’s close to it and takes an electron from that cell. Then a game of hot potato starts. A cascade of events occur leading to death within a cell. This causes premature aging and can lead to cancer. Antioxidants are substances that protect plants, for instance, in the environment. For example, they protect plants against smog, environmental pollution and ultraviolet radiation. These same properties that protect plants can be used to protect humans. With consumption of nutrients found within plants — such as vitamin C, vitamin E, beta carotene — these natural substances called antioxidants donate electrons and therefore neutralize the harmful effects of free radical damage.

If it works, why aren’t more people taking green tea? Are there any negative effects associated with it?
Green tea has caffeine in it, and caffeine doesn’t agree with certain people. For instance, it can lead to insomnia. It can lead to fibrocystic breast disease in women. It can lead to frequent urination. It can lead to elevated cholesterol and a host of other health problems. It can become addictive. Nevertheless, you will be pleased to know that green tea has one fifth the amount of caffeine that a typical cup of coffee has and one third the amount of caffeine that black tea has. Furthermore, there are extracts available which are virtually caffeine-free. As for why more people don’t take green tea, I don’t think they know about it. The Chinese have known about it for over 4,000 years, but it’s just now becoming available in extract form. People who may not want to drink the six to nine cups of tea that are needed to get maximum benefit can now take it in an extract form — in a capsule form.

Heart Disease Q&A

What is the prevalence of heart diseases in Americans?

Heart disease is the biggest killer of all of the chronic diseases. Cancer comes second. They say if you don’t die of heart disease you’re likely going to die of cancer, but heart disease is the one that gets us first. I think probably over 20 percent of deaths are heart related as this point in time.

How big of an impact does diet have on the heart?

Well, diet plays a big role. We know genetics is a big factor, too. That’s the thing with heart disease, there are just so many factors that come into play, including your level of physical activity, your genetics, and how you’ve managed your blood pressure and blood cholesterol levels. Now, we’re looking at homocystine levels and then the C-reactive protein that’s associated with inflammatory activity in the body. All of these things come into play. So, diet fits in with that whole scheme of things as a real important factor. The way I look at it a lot of times is that if you’ve got a family history of heart disease then its even more important for you to focus on a heart-healthy diet.

You just touched on C-reactive protein. What is CRP?

Essentially, it’s associated with increased inflammatory activity in the body. We know increased inflammatory action in the body puts stress on the heart. It also is related with a lot of other diseases like arthritis, for example. It is a known risk factor for heart disease, and so we are looking at it as a risk factor similar to things like blood cholesterol, low-density lipoprotein, high-density lipoprotein levels, homocystine and things like that.

How much would a healthy diet impact somebody’s health? Could it prevent heart disease?

The size of a role that diet plays in preventing heart disease probably depends on somebody’s genetics. However, studies like those done by Dr. Dean Arnish in San Francisco where he looked at the role of diet, he also incorporated exercise, stress reduction, and also enjoyable social situations. All of these things seemed to play a role, and any one alone was not really the whole piece of pie. Diet probably plays a pretty big factor, but I don’t think heart disease can be prevented by diet.

So a healthy diet is just one piece of the puzzle?

Right. You could be very physically active, in great shape from a lot of exercise and doing your yoga, reduce your stress, but if you have a junk diet then that’s another brick in that wall so to speak that’s missing and it’s going to fall down. A healthy diet is one of many bricks that help hold up the wall.

Specifically, how do fruits and vegetables affect the heart?

Fruits and vegetables impact the heart in a lot of ways actually. One of the basic things is that they are a good source of dietary fiber, and dietary fiber is associated with helping reduce the amount of cholesterol that gets absorbed or reabsorbed into the body. Dietary fiber is also good for overall intestinal health. The other things that are in all of these fruits and vegetables is a lot of important minerals. For example, a banana is very high in potassium, which is a real heart-healthy mineral. There are a lot of vitamins, of course. There is vitamin C in things like mangos, papayas and of course oranges. You can find vitamin A in colorful vegetables, including the green vegetables. So, carrots, red bell peppers, spinach and broccoli are all good sources of vitamin A.

How is vitamin A helpful?

Vitamin A is in the form of what’s called beta carotene and other carotenoids, and it functions as an antioxidant. Certain amounts of heart damage and blood vessel damage is thought to be related to oxidative stress, and so components such as beta carotene help reduce that oxidative stress on the body. There are also other chemicals in a lot of these fruits and vegetables that we call phytochemicals — phyto meaning plant and plant chemicals. A lot of them are very powerful antioxidants. They don’t function as nutrients so it’s not like we actually need them like we need vitamin C and vitamin A, which are required nutrients. These things aren’t really required but they enhance health if they are consumed.

Say someone hates fruit but he has got to work fruit into his diet, what are the most powerful players?

If you have a fruit-phobic person, usually I just encourage him to eat the ones he likes the most because they all have different strengths and weaknesses from a nutrient and phytochemical perspective. Variety really is the spice of life in terms of health. I guess if I was to pick just a few I would probably go with something like the colorful grapes for the nice phytochemicals that we know that those have. Wine is famous for that as well. Then I would want to have something that was a good source of vitamin C, and so that could be something like an orange or even pineapple. Then if you have your vitamin A and your vegetables, you want to think about the type of minerals that are important in these foods too and maybe throw in the banana for the potassium.

What about for vegetables? If you could only have one vegetable, what are the most powerful players?

Well, would it be better to have broccoli than a potato if you were real picky? Certainly, a potato is considered a vegetable, and potatoes have some strengths that often aren’t recognized. For example, they’re a real good source of vitamin B6, which we know is a heart protective nutrient. But I think if I was only going to go with say three vegetables, I would want to have probably three different colored vegetables — maybe an orange or yellow vegetable would be one, certainly a green vegetable would be another, and the other one could be like the red bell pepper, potato or a sweet potato. It’s really the variety that confers the most protection.

What is fiber’s role as it protects the heart?

We’re probably still just beginning to understand it, but fiber, on one hand, tends to bind up certain lipid-type of compounds, especially cholesterol and some of the bio acids that are released from our liver into the intestinal tract. What happens with these bio acids is they get reabsorbed into the body and reutilized. But if the fiber holds onto them and pulls them on through the body, and what happens is in order to make more of those bio acids, we need to use some of our body’s cholesterol to produce them. So it reflects a drain on our body’s cholesterol.

What are some of the foods that pack the most fiber?

Probably near the top of the list are beans and legumes, which often times don’t get recognized for their high levels of dietary fiber. Next would have to be fruits and vegetables. The grains, if they’re whole grains, are equivalent pretty much to fruits and vegetables. If you pick some of the cereals too, even some of the ready-to-eat cereals, are extremely high in fiber.

How much fiber should the average person get in a day?

The recommended intake of fiber is around 14 grams of fiber for every 1,000 calories in your diet. That’s sort of the standard recommendation. So for most people, that comes out to about around 25 to 30 grams per day.

What would be an example of what you would need to eat in a day to get that?

Generally, you could get that by eating according to the old food guide pyramid way. Most people kind of zone out when you mention the food guide pyramid because they’ve seen it too much. But the reality is if you get those number of servings from the grain group in terms of the whole grain products, the fruits, and you include beans as part of your high-protein food group, then you’re going to get that easily.

This article was reported by Ivanhoe.com, who offers Medical Alerts by e-mail every day of the week. To subscribe, go to: http://www.ivanhoe.com/newsalert/.

Treatment for Alzheimer’s Disease

Alzheimer’s disease, the most common form of dementia, is a progressive deterioration of the brain. It affects memory and thought, as well as communication and the ability to make decisions. Although the symptoms are usually mild at the onset of the disease, they often progress to such an extent that work and socializing become impossible.

Alzheimer’s usually afflicts people who are over the age of sixty. The most common symptoms are memory loss, inability to recognize family or friends, difficulty speaking and remembering words, personality changes, and difficulty making decisions. If you fear that yourself or someone you love may have Alzheimer’s, see a doctor for a diagnosis. This disease is incurable, but its progress can often be slowed down. The following supplements can help.

Supplements to treat Alzheimer’s Disease

• Acetyl-L-Carnitine
• Alpha-lipoic acid – Improves blood sugar levels so diabetics may be able to take less medication.
• B-complex vitamins
• Bilberry
• Carotenoids – Do not take for extended periods of time. Do not take high dosages if you have liver disease, are a smoker, or are exposed to asbestos. Beta carotene is perhaps the best known of the carotenoids because of its potential vitamin A activity. Diets rich in carotenoids, especially lycopene, may prevent prostate cancer. Other carotenoids may protect against ovarian cancer. Dietary sources rich in beta carotene and other provitamin A carotenoids include carrots, broccoli, yellow squash, corn, tomatoes, papayas, oranges, and dark green leafy vegetables.
• Coenzyme Q10
• EPA/DHA (fish oil)
• Ginkgo biloba
• Huperzine A – This Chinese herb should not be taken with other medications for Alzheimer’s disease.
• Inositol
• Magnesium
• NADH – Reduced and more active form of niacin.
• Phosphatidylcholine (Lecithin) – Use with caution if you have malabsorption problems, as this could exacerbate them.
• Phosphatidylserine – This product is particularly helpful to prevent Alzheimer’s, as well as toward the onset of the disease.
• Selenium
• Vinpocetine – Do not take if you are taking a blood thinner.
• Vitamin B9 (folic acid) – High doses can depete your body of other vitamins in the B complex.
• Vitamin B12 (cobalamin)
• Vitamin C
• Vitamin D
• Vitamin E – Take mixed tocopherols, the more active type of vitamin E. Consult healthcare provider first if you are taking a blood thinner.

Supplements to improve memory

• Acetyl-L-Carnitine
• Alpha-lipoic acid
• B-complex vitamins
• Coenzyme Q10
• EPA/DHA (fish oil)
• Ginkgo biloba
• N-acetylcysteine (NAC) – When taking NAC supplements, also take extra vitamin C, copper, and zinc.
• Phosphatidylcholine (Lecithin) – Use with caution if you have malabsorption problems, as this could exacerbate them.
• Phosphatidylserine
• Resveratrol
• Selenium
• Vinpocetine
• Vitamin A and mixed carotenoids – Use caution when taking vitamin A supplements because they have the potential to be toxic. Do not take for extended periods of time. Do not take high doses if you have liver disease, are a smoker, or are exposed to asbestos.
• Vitamin B9 (folic acid)
• Vitamin B12 (cobalamin)
• Vitamin C
• Vitamin E

What Should My Multivitamin Contain?

There are no perfect answers about what an ideal multivitamin should contain. Whether you’re a man, woman or child will help determine the product that’s best for you, as will your age, your dietary habits and the like. You may also need to take some nutrient as separate supplements, since multivitamins don’t always provide adequate quantities of some nutrients (for example, most multivitamins contain minimal quantities of calcium, because the full RDI of calcium is simply too bulky to fit into a single multivitamin pill). The following are some suggestions for nutrients to look for in a good multivitamin:

Vitamin A and Beta-carotene

Look for a product with more beta-carotene than vitamin A. Beta-carotene is a precursor to vitamin A (meaning the body converts it into vitamin A as needed). It’s far less toxic in large quantities, and it can be utilized by the body as needed. Moreover, it appears that beta-carotene offers more protection against cancer than vitamin A.

Benefits of Vitamin A

  • Assists in bone development and growth
  • Acts as a cofactor in essential enzyme reactions
  • Supports healthy testicular and ovarian function
  • Enables normal retinal function

Vitamin C

Vitamin C is an important antioxidant that should be supplied at levels well above the minimum requirements (60 milligrams). Some prominent researchers advocate taking huge amounts of vitamins C – tens of thousands of milligrams daily – while others suggest a more moderate 700 to 1,500 milligrams a day. Higher daily intake may only temporarily raise blood levels of vitamin C, though this could be beneficial. If you want to take more vitamin C than your multivitamin provides, you can easily take a separate supplement.

Benefits of Vitamin C

  • Prevents and treats scurvy
  • Acts as a powerful antioxidant
  • Assist in iron absorption
  • Helps treat anemia
  • Promotes collagen growth in connective tissue
  • Helps wound and broken bones heal
  • Treat urinary tract infections

Bioflavonoids

Many multivitamin formulas contain bioflavonoids, which are thought to enhance the action of vitamin C. Research shows that bioflavonoids also help reduce the risk of certain diseases.

Benefits of Bioflavonoids

  • Help metabolize carbohydrates and amino acids
  • Assist in formation of fatty acids
  • Support healthy blood cells, hair, skin, nerves, bones and male reproductive organs

Prevention of cardiovascular disease

A high dietary carotene intake is associated with a lower risk of cardiovascular disease. Beta-carotene may inhibit the oxidative damage to cholesterol and the lining of the arteries that initiates the process of hardening of the arteries (atherosclerosis). However, it appears that beta-carotene is less effective in protecting against cardiovascular disease than vitamin E, probably because vitamin E protects against oxidative damage to cholesterol better than beta-carotene.

Leukoplakia

Leukoplakias are white plaquelike lesions occurring anywhere in the mouth that are reactions to irritation, such as cigarette smoking or tobacco chewing. It is often a precancerous lesion that may develop into mouth or throat cancer. Beta-carotene has been found to be clinically effective in the treatment of leukoplakia. To date, there have been seven clinical trials showing that beta-carotene supplementation (30-180 mg per day) produces regression in anywhere from 15 to 71 percent of people with leukoplakia.

Low immunity and immune support

Beta-carotene has demonstrated a number of immune-enhancing effects. Originally it was thought that the immune-enhancing properties of beta-carotene were due to their being converted to vitamin A. researchers now know that carotenes exert many immune-system-enhancing effects independent of any vitamin A activity. In addition to a great number of experimental studies showing immune-enhancing effects with beta-carotene supplementation, there are also several clinical studies in both healthy human volunteers and those with evidence of impaired immune function. For example, in one study with healthy subjects, beta-carotene given at a dosage of 180 mg daily (approximately 300,00 IU of vitamin A activity) significantly increased the frequency of helper/inducer T cells (white blood cells that play a critical role in fighting infection) by approximately 30 percent after only seven days.

However, rather than supplementing the diet with synthetic beta-carotene, it may be more advantageous to use carotene from natural sources or increase the intake of carotene-rich foods. For example, in a study in healthy college students, better results in improving immune function were shown in the group that consumed approximately 15 mg beta-carotene per day from carrots compared to those who took 15 mg of synthetic beta-carotene.

Photosensitivity disorders

Beta-carotene has become the treatment of choice for photosensitivity disorders (skin rashes induced by the sun) even in conventional medical circles. It is most effective in the treatment of a condition named erythropoietic protoporphyria (EPP), while its effectiveness in other photosensitivity disorders has also been demonstrated, but not to the same degree. For this application, it is recommended that you consult a physician.

Available Forms

There are two primary sources of beta-carotene on the market; synthetic beta-carotene and natural carotene extracts. Natural beta-carotene is available derived from carrot oil, the algae Dunaliella salina (e.g., Betatene), and from palm oil (e.g., Caroplex, Caromin). The natural forms appear to offer advantages over the synthetic form in that they contain a broader range of carotenes, exert more antioxidant protection, and are better absorbed. Beta-carotene, whether natural or synthetic, is available in capsules or tablets.

Cautions and Warnings

Supplementation may cause the skin to turn a yellow to orange hue (carotenodermia). This change is not harmful.

Possible Side Effects

Supplementing the diet with beta-carotene has not been shown to produce any significant side effects other than a possible yellowing of the skin. Dosages greater than 180 mg per day may produce loose stools, but this side effect usually clears quickly and does not necessitate stopping treatment.

Food and Nutrient Interactions

Absorption of beta-carotene may be enhanced by taking it with food, particularly a meal with some fat or oil. High dosages of beta-carotene (e.g., greater than 15 mg / day) may increase the need for vitamin E. Olesra (a fat substitute) as well as sources of dietary fiber (psyllium, pectin, guar gum, etc.) may decrease the absorption of beta-carotene. Beta-carotene supplementation may decrease the absorption of other beneficial carotenes such as lutein and lycopene. A deficiency of zinc, vitamin C, protein, or thyroid hormone will impair the conversion of beta-carotene to vitamin A.