The last few years have been tough on us vitamin takers. If it’s not the FDA or the pharmaceutical companies waging war on supplements than it is the studies that purport that Vitamin E, Calcium, Multi-vitamins and Soy are a waste of money or are downright dangerous. The studies on E and Calcium have mostly been debunked so let’s work on debunking these other new studies. A special thank you to Dr. Chaney for his research and Dr. Jaime McManus, head of Shaklee Health Sciences.
“Don’t Throw Your Vitamins Away Yet”
Author: Dr. Stephen Chaney
“The Professor is annoyed. Two things really irritate me:
• Charlatans who cherry pick studies to “prove” that their snake oil supplements will cure what ails you.
• Doctors who proclaim that vitamins are a waste of money without understanding the science behind the studies they are quoting.
• Charlatans who cherry pick studies to “prove” that their snake oil supplements will cure what ails you.
• Doctors who proclaim that vitamins are a waste of money without understanding the science behind the studies they are quoting.
Are Multivitamins A Waste Of Money?
You’ve seen the headlines telling you that “the experts” have concluded that multivitamins are a waste of money. You might be wondering “What’s behind these headlines? Who are these experts, and what is their evidence?”
Let’s start at the beginning. The article (Gualler et al., Annals of Internal Medicine, 159: 850-851, 2013) that generated all of the headlines was an editorial, which means it is an opinion piece, not a scientific study. It represents the opinion of five very prominent doctors, but it is, at the end of the day, just their opinion. Many other well respected experts disagree with their opinion.
They based their editorial on three recently published studies:
• The first study reported that vitamin and mineral supplements did not decrease the risk of heart disease and cancer in healthy individuals (Fortmann et al., Annals of Internal Medicine, 159, doi: 10.7326/003-4815-159-12-201312170-00729)
• The second study reported that multivitamins did not affect cognitive function in healthy male physicians aged 65 and older (Gradstein et al, Annals of Internal Medicine, 159, 806-814, 2013)
• The third study concluded that multivitamins did not reduce the risk of a second heart attack in patients who had previously had a heart attack and were receiving appropriate medical therapy.
These were all large, well designed studies, so it would be tempting to conclude that the headlines were right. Maybe vitamins are a waste of money.
But, what if the whole underlying premise of these studies was flawed? Let’s examine that possibility by examining the flawed premises behind these and other studies.
What’s Wrong With These Studies?
#1) These studies were too narrowly focused.
Multivitamins and individual vitamins and minerals are not magic bullets. They are not drugs. They are meant to fill nutritional gaps in our diet - not prevent or cure disease. We should be asking whether holistic approaches can prevent or cure disease – not whether individual nutrients can do so.
One of the examples that I love to use, because it really made an impression on me as a young scientist, occurred at an International Cancer Symposium I attended more than 30 years ago. I attended a session in which an internally renowned expert was giving his talk on colon cancer. He said, “I can show you, unequivocally, that colon cancer risk is significantly decreased by a lifestyle that includes a high-fiber diet, a low-fat diet, adequate calcium, adequate B-vitamins, exercise and weight control. But I can’t show you that any one of them, by themselves, is effective.”
The question that came to me as I heard him speak was: “What’s the message that a responsible scientist or responsible health professional should be giving to their patients or the people that they’re advising?” You’ve probably heard experts saying:
• “Don’t worry about the fat content of your diet. It can’t be shown to increase the risk of colon cancer.”
• “Don’t worry about calcium. It doesn’t decrease the risk of colon cancer”
• “Don’t worry about B-vitamins. They don’t decrease the risk”
• “Don’t worry about fiber. It can’t be shown to decrease the risk either”
But, is that the message that we should be giving people - that nothing matters? Shouldn’t we really be saying what that doctor said many years ago – that a lifestyle that includes all of those things significantly decreases the risk of colon cancer?
#2) These studies were destined to fail.
It’s almost impossible to prove that any single intervention prevents disease when you are starting with a healthy population (something we scientists refer to as a primary prevention study).
For example, in the November 19th issue of "Health Tips From the Professor” I shared with you that even when you combine all of the published studies with tens of thousands of patients, it is impossible to prove that stain drugs prevent heart attacks in healthy individuals.
If you can’t show that statins prevent heart disease in healthy people, why would you expect to be able to show that vitamins or minerals prevent heart attacks in healthy people?
I can’t resist pointing out that this perfectly illustrates the pro-drug, anti-supplement bias that is so prevalent among many of my medical colleagues. I haven’t seen a single editorial or headline suggesting that statin drugs might be a waste of money for healthy individuals.
#3) These studies simply asked the wrong questions.
For example, the third study described in the editorial was asking whether multivitamins reduced the risk of a second heart attack in patients who were receiving “appropriate medical therapy”. What does “appropriate medical therapy” mean, you might ask? It means that those patients were on 4 or 5 drugs, with all of their side effects.
In reality the study was not asking whether multivitamins reduced the risk of a second heart attack. The study asked whether multivitamins had any additional benefits for individuals who were taking 4 or 5 drugs to reduce their risk of a second heart attack. That’s a totally different question.
There are lots of examples of this paradigm. For example, 17 years ago the Cambridge Heart Antioxidant Study showed that vitamin E significant decreased heart attack risk in patients with severe cardiovascular disease (Stephens et al, The Lancet, 347: 781-786, 1996). Patients in that study were taking one or two medications. However, in today’s world that would be considered unethical. The standard medical treatment for high risk heart disease patients today is 4 or 5 drugs, and when patients are receiving that many medications it is no longer possible to demonstrate a benefit of vitamin E. The story is similar for omega-3 fatty acids.
That poses a dilemma. What recent studies show is that individual nutrients don’t reduce the risk of a second heart attack in someone who is receiving “standard of care” medical treatment.
But that’s not the question I am interested in. I’d like to know whether natural approaches might be just as effective as the drugs or whether natural approaches might allow one to use fewer drugs or lower doses. I’d like to avoid all of the side effects of those drugs if I could.
What about you? What questions would you like answered? Do these studies answer those questions?
One of the examples that I love to use, because it really made an impression on me as a young scientist, occurred at an International Cancer Symposium I attended more than 30 years ago. I attended a session in which an internally renowned expert was giving his talk on colon cancer. He said, “I can show you, unequivocally, that colon cancer risk is significantly decreased by a lifestyle that includes a high-fiber diet, a low-fat diet, adequate calcium, adequate B-vitamins, exercise and weight control. But I can’t show you that any one of them, by themselves, is effective.”
The question that came to me as I heard him speak was: “What’s the message that a responsible scientist or responsible health professional should be giving to their patients or the people that they’re advising?” You’ve probably heard experts saying:
• “Don’t worry about the fat content of your diet. It can’t be shown to increase the risk of colon cancer.”
• “Don’t worry about calcium. It doesn’t decrease the risk of colon cancer”
• “Don’t worry about B-vitamins. They don’t decrease the risk”
• “Don’t worry about fiber. It can’t be shown to decrease the risk either”
But, is that the message that we should be giving people - that nothing matters? Shouldn’t we really be saying what that doctor said many years ago – that a lifestyle that includes all of those things significantly decreases the risk of colon cancer?
#2) These studies were destined to fail.
It’s almost impossible to prove that any single intervention prevents disease when you are starting with a healthy population (something we scientists refer to as a primary prevention study).
For example, in the November 19th issue of "Health Tips From the Professor” I shared with you that even when you combine all of the published studies with tens of thousands of patients, it is impossible to prove that stain drugs prevent heart attacks in healthy individuals.
If you can’t show that statins prevent heart disease in healthy people, why would you expect to be able to show that vitamins or minerals prevent heart attacks in healthy people?
I can’t resist pointing out that this perfectly illustrates the pro-drug, anti-supplement bias that is so prevalent among many of my medical colleagues. I haven’t seen a single editorial or headline suggesting that statin drugs might be a waste of money for healthy individuals.
#3) These studies simply asked the wrong questions.
For example, the third study described in the editorial was asking whether multivitamins reduced the risk of a second heart attack in patients who were receiving “appropriate medical therapy”. What does “appropriate medical therapy” mean, you might ask? It means that those patients were on 4 or 5 drugs, with all of their side effects.
In reality the study was not asking whether multivitamins reduced the risk of a second heart attack. The study asked whether multivitamins had any additional benefits for individuals who were taking 4 or 5 drugs to reduce their risk of a second heart attack. That’s a totally different question.
There are lots of examples of this paradigm. For example, 17 years ago the Cambridge Heart Antioxidant Study showed that vitamin E significant decreased heart attack risk in patients with severe cardiovascular disease (Stephens et al, The Lancet, 347: 781-786, 1996). Patients in that study were taking one or two medications. However, in today’s world that would be considered unethical. The standard medical treatment for high risk heart disease patients today is 4 or 5 drugs, and when patients are receiving that many medications it is no longer possible to demonstrate a benefit of vitamin E. The story is similar for omega-3 fatty acids.
That poses a dilemma. What recent studies show is that individual nutrients don’t reduce the risk of a second heart attack in someone who is receiving “standard of care” medical treatment.
But that’s not the question I am interested in. I’d like to know whether natural approaches might be just as effective as the drugs or whether natural approaches might allow one to use fewer drugs or lower doses. I’d like to avoid all of the side effects of those drugs if I could.
What about you? What questions would you like answered? Do these studies answer those questions?
What Was Overlooked In Those Studies
The studies did show conclusively that there were no harmful effects from supplementing except for high dose beta-carotene in smokers. Somehow that information never made it into the headlines.
The Bottom Line
• Don’t pay much attention to the reports that supplements don’t work and are a waste of money. Those studies are fundamentally flawed.
• Don’t pay much attention to the reports claiming that vitamins will hurt you. Except for beta-carotene in smokers the latest studies showed no evidence of harm.
• On the other hand, don’t expect miracles from your vitamins. If you spend your time sitting in front of the TV set eating pizza & drinking sodas, popping a vitamin pill won’t prevent much of anything.
• Finally, holistic approaches are often as effective as drug therapy – without the side effects. Your vitamins can be an important part of a holistic approach to better health that includes weight control, a good diet and exercise.”
A Letter from Dr. Jamie McManus MD:
The Bottom Line
• Don’t pay much attention to the reports that supplements don’t work and are a waste of money. Those studies are fundamentally flawed.
• Don’t pay much attention to the reports claiming that vitamins will hurt you. Except for beta-carotene in smokers the latest studies showed no evidence of harm.
• On the other hand, don’t expect miracles from your vitamins. If you spend your time sitting in front of the TV set eating pizza & drinking sodas, popping a vitamin pill won’t prevent much of anything.
• Finally, holistic approaches are often as effective as drug therapy – without the side effects. Your vitamins can be an important part of a holistic approach to better health that includes weight control, a good diet and exercise.”
A Letter from Dr. Jamie McManus MD:
Understanding the latest media attention on multivitamins—
“Many of you have probably seen the headlines regarding multivitamins and their inability to prevent chronic disease in the past few days—the result of three studies published in theAnnals of Internal Medicine.
Starting from a 30,000-foot view: The premise of these studies is the first problem—looking at the use of a multivitamin alone as a way to prevent disease. The purpose of a multivitamin is to fill in nutritional gaps and provide optimum levels of vitamins and minerals. It is well established that the vast majority of Americans fail to obtain even adequate levels of these nutrients.
Prevention of any disease is a multi-factorial process that has to include diet, weight management, and lifestyle. To expect to see disease prevention accomplished by virtue of taking a daily multivitamin is a flawed premise. So, why are these large-scale (and very expensive) studies undertaken? It is simply the model of research that scientists and physicians understand—studying a single drug to determine what effect it may have on a single disease. Studying nutrition is far more complex.
While a drug has a primary effect (usually something positive), they also have a myriad of side effects (which are usually negative and even life threatening). Every year pharmaceuticals are removed from the market because of these serious side effects. A study published in JAMA in 1998 showed that as many as 125,000 Americans die each year of properly prescribed pharmaceuticals—wow! When was the last time a vitamin was removed from the market?
Vitamins and minerals all have multiple positive functional roles to play in our bodies—which is why so many Americans pop a multi each day. People simply feel better when they take a multi because they are filling in those all too common nutrition gaps.
All three of these studies showed that multivitamins have an excellent safety profile. Well, of course they do—they are essential for life! The only “potential harm” that continues to be mentioned every time we have a study such as this published is the slight increased risk of lung cancer in smokers who took beta carotene . My response to that is—smokers: stop smoking!
Let me quickly summarize these studies. The largest one is another report from the Physician Health Study—previous publications of data from this large government funded study did show an association of reduced cancer associated with multivitamin usage.
The next study looked at cognitive decline in physicians--who are at the upper end of intelligence scale and pretty well nourished. Showing a significant change in cognitive decline in this population is going to take some intervention beyond a multi—as this population is most likely doing lots of right things to protect their brain function.
The third study tried to show that higher doses of specific vitamins decrease the likelihood of a second heart attack in folks who have already had a heart attack. Hmmm maybe we should look at weight reduction, cholesterol, blood pressure lowering, and blood sugar management as opposed to putting the burden of prevention of a second heart attack in someone with heart disease on vitamins!
I have been recommending a multivitamin (and beyond) to my patients, and consumers in general, for my entire 30 years as a physician—and nothing in these studies changes my mind. The statistics on inadequacies in our American diet are clear—most everyone is deficient in multiple nutrients. Here at Shaklee, we have the Landmark study, published in the journal Nutrition in 2007 that showed a nice correlation of better health with multiple supplement usage, starting with a multivitamin. We have published studies over five decades on our flagship multivitamin, Vita Lea and have over 100 published studies that validate the connection of nutrition and health. I urge you to continue taking your Shaklee supplements—but also, to remember the importance of eating healthfully, avoiding fast foods, and getting to a healthy weight on your journey to better health.”
And for the grand finale finish on multi-vitamins….
“20 Little-Known Reasons to Take a Quality Daily Multivitamin”
by Dr. Julian Whitaker
“Most everyone knows that taking a quality, daily multivitamin and mineral supplement can help protect against many degenerative disorders such as heart disease and osteoporosis, as well as run-of-the-mill illnesses such as infections or the common cold.
Here are 20 other lesser-known ways a multi can help promote optimal health and well-being:
1. Support healthy aging. As you get older, your body has a harder time absorbing nutrients from food. At the same time, your nutritional needs increase.
2. Correct nutritional deficiencies caused by prescription drugs and surgery and nutritionally wasting health conditions such as diabetes. Along with aging, there are several other factors that can make you more susceptible to nutritional deficiencies, including these common culprits.
3. Improve short-term memory. According to a meta-analysis of 10 randomized, placebo-controlled trials, taking a multivitamin can result in improvements in short-term memory.
4. Boost energy levels. Several studies have demonstrated that taking a daily multivitamin and mineral supplement is associated with increased energy levels.
5. Detoxify your body. The robust levels of minerals, antioxidants, and B-complex vitamins present in a high-quality daily multi help clear toxins from the body, facilitate enzymatic reactions required for detoxification, and keep the liver and other organs in tip-top shape.
6. Maintain muscle strength. Many of the problems with muscle aging are associated with free radical damage, and an antioxidant-rich daily multivitamin can help keep free radicals in check. Vitamin D has also been shown to improve muscle strength in older people.
7. Prevent falls. Numerous studies have found that a daily multivitamin and mineral supplement— particularly one with therapeutic dosages of vitamin D (at least 1,000 IU) and calcium (1,000 mg)—can improve balance and reduce risk of falls.
8. Restore sense of smell. Anosmia, the inability to detect odors, can be caused by a deficiency of zinc. Low levels of vitamins B12 and A along with copper are also associated with changes in sense of smell (and taste).
9. Protect against hearing loss. Several studies have found a correlation between hearing loss and deficiencies in B-complex vitamins. A more recent study also found that people with elevated homocysteine levels had a 64 percent increased risk of hearing loss, and the best way to lower homocysteine levels is with B-complex vitamins.
10. Improve your skin. Research has shown that beta-carotene and vitamins C and E are important for maintaining healthy, younger-looking skin.
11. Prevent asthma and allergies. People with asthma and those prone to allergies often have depleted levels of vitamin C, zinc, selenium, and magnesium.
12. Prevent diabetes complications. As I mentioned earlier, diabetes is a nutritionally-wasting condition, putting those who have it at dramatically increased risk of other problems (or complications)—especially ones that affect the eyes, nerves, blood vessels, kidneys, and extremities. The best way to prevent these complications is by taking a potent, daily multivitamin and mineral supplement.
13. Boost mood. Many studies have found that a daily multi has positive effects on mood and emotional well-being.
14. Manage Stress. Along with boosting mood, research has shown that a multivitamin—particularly one containing therapeutic dosages of B-complex vitamins—can help reduce stress and anxiety.
15. Enhance weight loss. A randomized, double-blind study of obese women found that those taking a daily multivitamin and mineral supplement lost an average of 7.9 pounds, compared to 2 pounds for those taking calcium and half a pound in the placebo group.
16. Improve sexual function. The organs and glands that are responsive to sexual hormones are particularly vulnerable to free radical damage, so taking an antioxidant-rich daily multivitamin can help ensure peak performance and function.
17. Prevent dry eyes. Most people know that vitamins, especially antioxidants, are essential for maintaining overall vision. But by the time you reach age 65, a lifetime of free radical damage has taken its toll, and our eyes produce (on average) 40 percent less lubrication. That’s why shoring up on these crucial nutrients can help correct or prevent the problem from developing in the first place.
18. Stop telomere erosion. Chromosomes are tightly coiled, rod-like structures made up of proteins and one double-helix–shaped molecule of DNA encoded with your genome: the blueprints for your growth, development, and physiological function. And at the tips of every chromosome are protective “caps” called telomeres, which naturally get shorter as we age. Research has found that taking a daily multi can help slow and even reverse this erosion.
19. Reduce cravings for alcohol. Research suggests that people who have problems with alcohol can often gain better control over their drinking by making sure they have adequate levels of B-complex vitamins, calcium, and magnesium.
20. Prevent dental problems. Vitamin C plays a key role in the prevention of gum disease, as it helps maintain the integrity of the supporting structures of the oral tissues. Other antioxidants, including vitamins A and E as well as selenium, have also been shown to improve the health of the gums. Perhaps even more important is zinc. This mineral stabilizes cellular membranes and inhibits plaque growth. Deficiencies in both zinc and vitamin A are also common in patients with periodontal disease”
And about soy…
Dr. Jamie McManus/Shaklee on Soy
“For 50 years, Shaklee scientists have recommended soy protein consumption as part of a healthy diet. However, today we are also well aware of the great confusion among consumers and even health professionals about the health benefits of soy, because of a few very limited studies on soy that have received much attention on the internet.
We decided to consult an independent scientific expert on soy to review all the latest data for us and prepare a comprehensive review.
We chose Mark Messina, PhD, an adjunct associate professor at Loma Linda University and the Executive Director of the Soy Nutrition Institute. Dr. Messina, an acknowledged leader in soy research, has made studying the health affects of soy his focus for over 20 years and has published more than 60 scientific papers and given more than 500 presentations on soy foods to health professionals around the world.
From his comprehensive scientific white paper prepared exclusively for Shaklee, Dr. Messina produced a summary update on soy: Soy and Your Health: An Update on the Benefits, summarized the latest science on the health benefits of soy consumption. It covered a wide range of topics such as how a daily moderate intake of soy can promote heart health and bone health, potentially alleviate certain menopause symptoms and possibly even help keep skin looking beautiful.”
We decided to consult an independent scientific expert on soy to review all the latest data for us and prepare a comprehensive review.
We chose Mark Messina, PhD, an adjunct associate professor at Loma Linda University and the Executive Director of the Soy Nutrition Institute. Dr. Messina, an acknowledged leader in soy research, has made studying the health affects of soy his focus for over 20 years and has published more than 60 scientific papers and given more than 500 presentations on soy foods to health professionals around the world.
From his comprehensive scientific white paper prepared exclusively for Shaklee, Dr. Messina produced a summary update on soy: Soy and Your Health: An Update on the Benefits, summarized the latest science on the health benefits of soy consumption. It covered a wide range of topics such as how a daily moderate intake of soy can promote heart health and bone health, potentially alleviate certain menopause symptoms and possibly even help keep skin looking beautiful.”
Soy and Your Health: An Update on the Benefits
By: Mark Messina, PhD
“Soyfoods have been a part of Asian diets for centuries. Today, there is a growing interest in these foods among westerners because of their proposed health benefits and also because their versatility makes them valuable for replacing meat and dairy foods in the diet. Soybeans provide excellent nutrition and contain a number of biologically active components that collectively may be responsible for a variety of health benefits. However, most of the interest in soy is due to their isoflavone content. Isoflavones have been rigorously studied for their protective effects against several chronic diseases including osteoporosis, coronary heart disease and certain forms of cancer.
Soy Isoflavones
Isoflavones are essentially unique to soyfoods; no other commonly-consumed foods contain enough to impact health [1]. Although they are among a group of naturally-occurring compounds known as phytoestrogens (plant estrogens), isoflavones are much different from the hormone estrogen. In fact, they are most accurately classified as SERMs (selective estrogen receptor modulators) [2]. Other examples of SERMs are the breast cancer drug tamoxifen and the breast cancer and osteoporosis drug, raloxifene. The effects of SERMs vary depending upon
a variety of circumstances. SERMs like isoflavones may have estrogen-like effects, but depending on a number of factors, they may also have effects opposite to those of estrogen or no effects at all in tissues that are affected by estrogen. Therefore, looking at the health effects of estrogen doesn’t provide much information about how isoflavones act. The only way to learn about the effects of isoflavones is to look directly at their biological activity in studies.
Soybean Nutrition
Soybeans are unique among legumes, a group of foods that includes beans, peas, and lentils, because they are much higher in protein and fat than other beans, and lower in carbohydrate [3]. The fat in soybeans is primarily a combination of heart-healthy essential polyunsaturated omega-6 and omega-3 fatty acids [4]. This makes soybeans one of the few plant foods to provide both of the essential fatty acids. The carbohydrate in soy is comprised primarily of simple sugars that have been shown in some studies to act as prebiotics, thereby stimulating the growth of healthy bacteria in the colon. Soyfoods are also good sources of B vitamins and minerals such as potassium, iron and sometimes calcium.
Soybeans are perhaps best known for their high protein content. Although soybeans contain trypsin inhibitors, compounds which can interfere with the digestion of protein, the normal processing used to produce soyfoods inactivates these compounds. As a result, protein in soy is very well digested; digestion typically exceeds 90 percent. For this reason, and because of its excellent amino acid profile, soy protein is comparable in quality to the protein in animal
products [5].
Soyfoods and Heart Disease
Research suggests that incorporating soyfoods into the diet may decrease LDL-cholesterol (the bad cholesterol) by as much as 8 percent [6]. When soyfoods replace conventional sources of protein in western diets, saturated fat intake is reduced and polyunsaturated fat intake is increased. As a result, blood cholesterol levels will be lowered. That soyfoods contain a combination of omega-6 and omega-3 fatty acids is especially important for reducing risk of heart disease [7]. In addition to the healthy fat found in soy, soy protein has been shown to directly reduce levels of blood cholesterol. The Food and Drug Administration awarded a health claim for soyfoods and coronary heart disease on this basis in 1999. The effects of soy protein are comparable to cholesterol-lowering benefits of soluble fiber, the kind found in oat bran. In addition to lowering LDL-cholesterol, soyfoods give a modest boost to HDL-cholesterol, which is protective against heart disease, and reduces levels of triglycerides (another fatty compound in the blood that can raise heart disease risk). Finally, soyfoods may reduce heart disease risk in ways that are independent of their effects on cholesterol. For example, soyfoods may lower blood pressure [8] and research indicates that isoflavones directly improve the health of the arteries [9]. Therefore, even people with normal cholesterol levels can benefit by consuming soyfoods.
Soyfoods and Breast Cancer Risk
In Asian countries, where soyfoods are a usual part of the diet, breast cancer rates are much lower than in western countries. This observation helped fuel speculation that soyfoods reduce breast cancer risk. However, after years of research, it is not clear that women who begin to consume soy foods in adulthood will lower their risk of cancer. Rather, the protective effects appear to be related to early soy consumption. That is, women who consumed these foods in childhood and/or the teen years may have a lower risk for breast cancer later in life. Protective
effects of soy are thought to be due to actions of soy isoflavones on the developing breast in ways which make breast cells more resistant to being transformed into cancer cells later in life
[10, 11]. Studies conducted in China and the United States show that the consumption of modest amounts of soy—1 to 1_½ servings per day—is associated with a 25 to 50% reduction in risk. Although the hypothesis that early soy intake is protective against breast cancer remains speculative, because the amount of soy needed for benefit is modest and soyfoods provide good nutrition, there is no reason to wait for the results of future research before encouraging young
girls to consume soy.
Prostate Cancer
In studies of Asian populations, consumption of unfermented soyfoods such as tofu and soymilk, is associated with a reduced risk for prostate cancer. These studies show that Asian men who consume about two servings of soyfoods daily are about 30 to 50% less likely to have prostate cancer than Asian men who consume little soy [12]. Some evidence also shows that, in men with prostate cancer, eating soyfoods may slow the rise of blood levels of prostate specific antigen (PSA), a protein associated with tumor growth [13]. Also, an important study in prostate cancer patients indicated that consuming soy isoflavones could reduce levels of an enzyme involved in cancer metastasis [14]. Finally, consumption of soyfoods may reduce some of the side effects associated with radiation therapy for prostate cancer treatment [15].
Osteoporosis
Because isoflavones exert estrogen-like effects under certain circumstances, scientists have been studying whether soyfoods reduce risk of osteoporosis. Two important studies show that among Asian postmenopausal women, those who are in the upper quarter of soy intake are about 1/3 less likely to suffer a fracture [16, 17]. However, studies in which postmenopausal women have been administered soyfoods, soy protein or isoflavone supplements have produced mixed results. Some studies show an improvement in bone mineral density and some don’t. Thus,
more research in this area is needed before conclusions can be made. However, because some soyfoods are good sources of calcium, and all soy products provide high-quality protein, which is important for strong bones, soyfoods can play a beneficial role in diets aimed in promoting bone health regardless of the effects of isoflavones.
Skin Health
A number of cosmetics and lotions that contain soy extracts have been shown in clinical studies to improve the health and appearance of skin. Recently, there has been interest in the effects of dietary intake of isoflavones on the skin as well. Isoflavones bind to estrogen receptors in the skin and the hormone estrogen is associated with improved skin appearance. Several small studies suggest that isoflavone intake improves skin elasticity and increases collagen synthesis
[18-22]. Although it is too early for definitive conclusions about the benefits of soy for skin, research in this area is promising.
Hot Flashes
The drop in estrogen levels that occurs in menopause is linked with the onset of hot flashes. The estrogen-like properties of isoflavones may be one reason why western women report having hot flashes to a much greater extent than women in Japan. More than 50 clinical trials have evaluated the effects of isoflavone-containing products on the alleviation of menopausal symptoms. The most recent analysis of this research, which includes 19 studies, shows very clearly that isoflavones are effective [23]. On average, isoflavones produce a 50% decrease in
the frequency and severity of hot flashes. The amount of isoflavones found in two servings of traditional soyfoods appears to be sufficient to produce this benefit.
Intake Recommendations
The 2010 U.S. Dietary Guidelines call for increasing the intake of plant protein. Soyfoods are an excellent way to do just that. The quality of soy protein is comparable to animal protein but soyfoods contain only minimal amounts of saturated fat. There is also intriguing evidence indicating that, independent of the nutrients they offer, soyfoods provide a number of health benefits. Based on Asian intake as well as the amounts of soy shown to be beneficial in clinical studies, a good goal is to consume about 15 to 25 grams of soy protein per day. These amounts are provided by about 2 to 4 servings of soyfoods.”
About the Author:
Dr. Mark Messina is an adjunct associate professor at Loma Linda University and the Executive Director of the Soy Nutrition Institute. He has been studying the health effects of soy for more than 20 years and has published more than 60 scientific papers and given more than 500 presentations on soyfoods to health professionals.
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