This should help clear some things up!
SOY PROTEIN by Ray Sahelian, M.D.
Soy protein is used in a variety of foods such as imitation meats, beverage powders, cheeses, non-dairy creamer, frozen desserts, salad dressings, soups, infant formulas, and breakfast cereals. Soy protein is also available as a supplement in powder form and used mostly by body builders as an additional protein source for increasing muscle mass and by those who wish to improve cardiovascular health. Some women use soy protein after menopause.
How is Soy Protein available?
You can find soy protein supplement in various forms: soy protein powder and soy protein shake, soy protein bar and soy protein isolate.
Benefit of Soy Protein supplement
Soy protein may benefit in hypertension and menopause. Soy protein may be beneficial in maintaining healthy lipid profiles and in osteoarthritis. Soy protein supplement, along with creatine, are helpful in bodybuilding.
Soy protein vs Whey Protein
My thoughts are that the body likes to be exposed to a variety of substances, so it may be a good idea to use both soy and Whey protein either together or to alternate their use.
Soy protein as good as whey protein for muscle building
Weight lifters and other athletes often use whey protein supplements and have been less interested in using soy protein thinking that since soy is a vegetable, muscle building would not be as effective as whey protein derived from milk. However, a study in rats indicates that soy and whey protein equally help restore muscle mass after exercise on a treadmill for two hours. After exercise, ingesting protein helps accelerate protein synthesis in muscle tissue.
Soy protein and Cholesterol
Two servings a day of soy protein -- such as that found in tofu, soy milk or soy powder -- can lower cholesterol levels by a small amount as long as the raw soy is uncooked. Soy-fortified muffins, cereals or nutritional bars in which the soy protein was baked at high temperatures do not provide the benefit. A small drop in low-density lipoprotein, the so-called bad cholesterol that can lead to heart disease, can be gained from eating uncooked soy protein in the form of soy milk or tofu. Cooking the tofu does not destroy the key proteins because they have been stabilized. The health benefit also is found in such products as soy nuts, soy powder sprinkled on food or in milkshakes, or edamame, a raw or parboiled edible form of soybeans popular in Japan.
Soy Protein and Blood Lipids
A meta-analysis of the effect of soy protein supplementation on serum lipids.
Am J Cardiol. 2006 Sep 1;98(5):633-40. Reynolds K, Chin A, Lees KA, Nguyen A, Bujnowski D, He J. Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana, USA.Some, but not all, studies have shown that soy protein intake decreases total and low-density lipoprotein cholesterol and triglycerides and increases high-density lipoprotein cholesterol. The objective of this meta-analysis was to examine the effect of soy protein supplementation on serum lipid levels in adults. Meta-regression analyses showed a dose-response relation between soy protein and isoflavone supplementation and net changes in serum lipids. These results indicate that soy protein supplementation reduces serum lipids among adults with or without hypercholesterolemia.
In conclusion, replacing foods high in saturated fat, trans-saturated fat, and cholesterol with soy protein may have a beneficial effect on coronary risk factors.
Soy Protein and Heart Health
Soy proteins alter the ratio of different lipids in the blood, in a way that should reduce the risk of cardiovascular diseases, in healthy subjects. Lately, soy has received special attention, in particular soy proteins and soy "isoflavones" -- estrogen-like plant compounds. As described in the American Journal of Clinical Nutrition, the study included 35 healthy men about 28 years old, who took three different supplements for periods of eight weeks: "regular" milk proteins, soy proteins with low isoflavone content, and soy with high isoflavone content. The different supplements were given in a random order, each separated by a one-month break, to insure the sequence didn't influence the findings.
Ratios of total cholesterol to HDL ("good") cholesterol and LDL ("bad") cholesterol to HDL were significantly lower with both soy supplements, compared to the regular milk protein. Soy proteins reduced lipid levels, even in healthy individuals. Levels of other blood lipids were also modified in a favorable way in this group of young subjects. Source: American Journal of Clinical Nutrition, February 28, 2006.Soy protein and Hypertension
Soybean protein may help lower blood pressure. The use of soy protein dietary supplements may help reduce systolic and diastolic blood pressure in patients with early hypertension, according to a report in the July 5th, 2005 issue of the Annals of Internal Medicine. Findings from epidemiologic studies have suggested an inverse link between vegetable protein intake and blood pressure. Dr. Jiang He, of Tulane University in New Orleans, and colleagues assessed blood pressure changes in 302 adults who were randomized to receive soy protein supplements or carbohydrate control for 12 weeks. Compared with controls, soy protein treated subjects experienced a significant drop in both systolic and diastolic blood pressure. These results, the authors conclude, "provide new evidence supporting dietary soybean protein supplementation to prevent and treat hypertension."
Soy Protein for Renal Transplant Patients
A soy protein diet improves endothelial function in renal transplant patients. This effect seems to be strictly dependent on soy intake as it disappears after soy withdrawal and is mediated by an increase in the l-arginine / ADMA ratio, independently of change in lipid profile, oxidative stress or isoflavones.
Soy protein isolate, menopause, and bone health
Effects of soy protein isolate and moderate exercise on bone turnover and bone mineral density in postmenopausal women.
Menopause. 2007 Jan 8; Evans EM, Racette SB, Van Pelt RE, Peterson LR, Villareal DT. From the Section of Applied Physiology, Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, St. Louis, MO.
The aim of this study was to assess the independent and additive effects of soy protein isolate and moderate-intensity exercise on bone turnover and bone mineral density (BMD). This study used a placebo-controlled, double-blind (soy), randomized 2 (soy protein isolate versus milk protein isolate x 2 (Exercise vs no EX) design.
CONCLUSIONS:: In postmenopausal women soy protein isolate reduces bone turnover with no impact on BMD over 9 months; moderate-intensity endurance exercise training did not favorably alter bone turnover and had no impact on BMD; and there were no additive effects of soy and exercise on bone turnover or BMD.
Soy Supplement and Hormone Level
Dose effect of soy supplementation in prostate cancer: A pilot study.
Oncol Rep. 2006 Dec;16(6):1221-4. van Veldhuizen PJ, Thrasher JB, Ray G, Cherian R, Ward J, Holzbeierlein J, Gutow S, Banerjee SK. Veteran Affairs Medical Center, Kansas City, MO 64128, USA
We performed a pilot study to determine the dose effect of soy supplement on serum hormonal levels, estrogen receptor alpha (ERalpha) and androgen receptor (AR) expression in patients scheduled to undergo prostatectomy. Cohorts of 3-4 eligible patients received escalating doses of a commercial soy supplement, Flav-ein, from the time of study enrollment until prostatectomy. Serum levels of prostate specific antigen (PSA), testosterone, and estrogen were measured at study enrollment and prior to prostatectomy. AR and ERalpha expression was evaluated in the pretreatment biopsy specimen and post-treatment prostatectomy specimen using immunohistochemical analysis. A total of 13 patients were enrolled in this pilot study and 11 patients were assessable for response. With soy supplementation, serum testosterone levels decreased in 9 of 11 patients and estrogen levels decreased in 8 of 10 patients in a dose-dependent manner. There was a variable effect on ERalpha expression with downregulation of receptor expression seen at the highest dose level. There was no effect on AR expression. In conclusion, supplementation with this commercial soy product produced a consistent decrease in serum sex hormone levels. Additional studies are needed to evaluate a potential dose effect on ERalpha expression.
Soy Protein Research Update
Lipid-lowering effect of 2 dosages of a soy protein supplement in hypercholesterolemia.
Adv Ther. 2005 Mar-Apr;22(2):175-86.
The lipid-lowering effect of a soy-based protein supplement was evaluated in an 8-week randomized, placebo-controlled trial in patients with hypercholesterolemia. A total of 117 patients (63 men and 54 women) received soy protein, either 15 or 25 g/d or placebo. In the active treatment groups low-density lipoprotein cholesterol levels decreased significantly by 5.9% and 1.1% respectively, but increased by 3.6% with placebo. Total serum cholesterol and apolipoprotein B levels changed significantly in a similar manner. High-density lipoprotein cholesterol, triglycerides, homocysteine, folic acid, and vitamin B12 levels did not change significantly compared with baseline in any of the study groups. All preparations were well tolerated. Soy protein 25 g/d was twice as effective as 15 g/d. In conclusion, soy protein supplementation may effectively reduce serum cholesterol levels and therefore is likely to diminish the risk for cardiovascular disease.
Meta-analysis of the effects of soy protein containing isoflavones on the lipid profile 1,2,3
American Journal of Clinical Nutrition, Vol. 81, No. 2, 397-408, February 2005
Background: Convincing evidence shows that soy protein intake has beneficial effects on lipid changes, but it is unclear which components of soy protein are responsible. Objective: We conducted a meta-analysis to identify and quantify the effects of soy protein containing isoflavones on the lipid profile. Results: Soy protein with isoflavones intact was associated with significant decreases in serum total cholesterol (by 0.22 mmol/L, or 3.77%), LDL cholesterol (by 0.21 mmol/L, or 5.25%), and triacylglycerols (by 0.10 mmol/L, or 7.27%) and significant increases in serum HDL cholesterol (by 0.04 mmol/L, or 3.03%). The reductions in total and LDL cholesterol were larger in men than in women. Initial total cholesterol concentrations had a powerful effect on changes in total and HDL cholesterol, especially in subjects with hypercholesterolemia. Studies with intakes >80 mg showed better effects on the lipid profile. The strongest lowering effects of soy protein containing isoflavones on total cholesterol, LDL cholesterol, and triacylglycerol occurred within the short initial period of intervention, whereas improvements in HDL cholesterol were only observed in studies of >12 wk duration. Tablets containing extracted soy isoflavones did not have a significant effect on total cholesterol reduction. Conclusions: Soy protein containing isoflavones significantly reduced serum total cholesterol, LDL cholesterol, and triacylglycerol and significantly increased HDL cholesterol, but the changes were related to the level and duration of intake and the sex and initial serum lipid concentrations of
the subjects.
Soy protein may alleviate osteoarthritis symptoms.
Phytomedicine. 2004 Nov;11(7-8):567-75.
Alternative and complementary therapeutic approaches, such as the use of a wide array of herbal, nutritional, and physical manipulations, are becoming popular for relieving symptoms of osteoarthritis. The present study evaluated the efficacy of soy protein supplementation in relieving the pain and discomfort associated with osteoarthritis. One hundred and thirty-five free-living individuals (64 men and 71 women) with diagnosed osteoarthritis or with self-reported chronic knee joint pain not attributed to injury or rheumatoid arthritis were recruited for this double-blind, placebo-controlled, parallel design study. Study participants were assigned randomly to consume 40 g of either supplemental soy protein or milk-based protein (MP) daily for 3 months. Overall, soy protein improved osteoarthritis -associated symptoms such as range of motion and several factors associated with pain and quality of life in comparison to MP. However, these beneficial effects were mainly due to the effect of soy protein in men rather than women. This study is the first to provide evidence of possible beneficial effects of soy protein in the management of osteoarthritis. Examining and verifying the long-term effects of soy protein on improving symptoms of osteoarthritis, particularly in men, is warranted. soy protein
soy protein powder soy protein shake soy protein isolate whey vs soy protein soy protein bar.
A University of Missouri-Columbia researcher has shown that estrogen may protect against colon cancer. In addition, the researcher also found that soy protein may help minimize the number and size of tumors that do occur.
Soy versus whey protein bars: Effects on exercise training impact on lean body mass and antioxidant status.
Nutr J. 2004 Dec 08;3(1):22.
Although soy protein may have many health benefits derived from its associated antioxidants, many male exercisers avoid soy protein. This is due partly to a popular, but untested notion that in males, soy is inferior to whey in promoting muscle weight gain. This study provided a direct comparison between a soy product and a whey product. METHODS: Lean body mass gain was examined in males from a university weight training class given daily servings of micronutrient-fortified protein bars containing soy or whey protein (33 g protein/day, 9 weeks, n = 9 for each protein treatment group). Training used workouts with fairly low repetition numbers per set. A control group from the class (N = 9) did the training, but did not consume either type protein bar. RESULTS: Both the soy and whey treatment groups showed a gain in lean body mass, but the training-only group did not. The whey and training only groups, but not the soy group, showed a potentially deleterious post-training effect on two antioxidant-related related parameters.
CONCLUSIONS: Soy and whey protein bar products both promoted exercise training-induced lean body mass gain, but the soy had the added benefit of preserving two aspects of antioxidant function.
Isolated soy protein consumption reduces urinary albumin excretion and improves the serum lipid profile in men with type 2 diabetes mellitus and nephropathy.
J Nutr. 2004 Aug;134(8):1874-80.
Soy protein was shown to exhibit several beneficial effects on renal function in nondiabetic patients with nephropathy, and to improve serum lipids. This study examined the effects of isolated soy protein consumption on urinary albumin excretion, serum lipids, plasma amino acids, and isoflavones in diabetic patients with nephropathy. Male patients (n = 14) with type 2 diabetes and nephropathy were followed in a crossover design for 7 mo. The study comprised two 8-wk intervention periods, placed between a 4-wk lead-in and two 4-wk washout periods. In the 2 intervention periods, 0.5 g/(kg. d) of the dietary protein was provided as either isolated soy protein (ISP) or casein, in random order. The findings indicate that isolated soy protein consumption improves several markers that may be beneficial for type 2 diabetic patients with nephropathy.
Should diabetics drink more soy and less milk?
Kidney function of people with type 2 diabetes seems to be improved by dietary soy protein. A study of 14 older men with diabetes-related kidney disease found that adding a soy product to their diets reduced the amount of protein in their urine -- an indicator of improved kidney function. It's unclear why soy protein might aid in diabetic kidney disease, but estrogen-like plant compounds called isoflavones could be involved, said one of the researchers Dr. Erdman, a professor of food science at the University of Illinois at Urbana-Champaign. Isoflavones are types of flavonoids found in plants. The main sources for isoflavones are soy products, beans, peas, nuts, grain products, coffee, tea and certain herbs such as red clover. Genistein is one of the best known and studied isoflavones. Compounds in plants that have estrogen-like properties are called phytoestrogens. Most isoflavones have phytoestrogenic properties. For eight weeks, men in the study used an isolated soy protein powder that could be added to a drink or food. For another eight weeks, they used a milk-based protein powder. The goal, Erdman explained, was to have the men replace part of their usual protein intake with the soy or milk protein; however, the patients failed to follow the diet instructions and instead added the soy protein powders to their normal routine. Yet even with the extra protein intake, the men's excretion of protein in urine fell an average of nearly 10 percent when they consumed the soy product In contrast, protein levels in the urine increased with the milk-based powder. In addition, eight weeks on the soy powder boosted the men's levels of heart-healthy HDL cholesterol by about four percent, while it tended to dip while the men were on the milk protein. Blood tests showed that as the men's isoflavone levels increased, their protein excretion declined. SOURCE: Journal of Nutrition, August 2004.
Dr. Sahelian comments: Lately I have been buying unsweetened soy milk and adding a little bit of the natural no-calorie sweetener stevia to sweeten the drink.
Soy protein isolates of varying isoflavone content exert minor effects on serum reproductive hormones in healthy young men.
J Nutr. 2005 Mar;135(3):584-91.
Inverse associations between soy and prostate cancer and the contribution of hormones to prostate cancer prompted the current study to determine whether soy protein could alter serum hormones in men. Thirty-five men consumed milk protein isolate (MPI), low-isoflavone soy protein isolate (SPI) (low-iso SPI; 1.64 +/- 0.19 mg isoflavones/d), and high-iso SPI (61.7 +/- 7.35 mg isoflavones/d) for 57 d each in a randomized crossover design. Twenty-four-hour urine samples indicated that urinary isoflavones were significantly increased by the high-iso SPI relative to the low-iso SPI and MPI. Serum collected on d 1, 29, and 57 of each treatment revealed that dihydrotestosterone (DHT) and DHT/testosterone were significantly decreased by the low-iso SPI [9.4% and 9.0%, respectively] and the high-iso SPI [15% and 14%, respectively, compared with the MPI at d 57. Other significant effects included a decrease in testosterone by the low-iso SPI relative to the MPI (P = 0.023) and high-iso SPI at d 29; an increase in dehydroepiandrosterone sulfate by the low-iso SPI relative to the MPI at d 29 and relative to the MPI and high-iso SPI at d 57; and increases in estradiol and estrone by the low-iso SPI relative to the MPI at d 57. In conclusion, soy protein, regardless of isoflavone content, decreased DHT and DHT/testosterone with minor effects on other hormones, providing evidence for some effects of soy protein on hormones. The relevance of the magnitude of these effects to future prostate cancer risk requires further investigation.
Hormonal response to diets high in soy or animal protein without and with isoflavones in moderately hypercholesterolemic subjects.
Nutr Cancer. 2005;51(1):1-6. Goldin BR, Brauner E, Adlercreutz H, Ausman LM, Lichtenstein AH.
Department of Family Medicine and Community Medicine, Tufts University School of Medicine, Boston, MA
Consumption of soy protein has been associated with altered risk of developing endocrine-regulated cancers. This study was designed to assess the independent effect of soy relative to animal protein and soy-derived isoflavones on circulating estrogen and androgen concentrations in postmenopausal women and older men. Forty-two subjects (> 50 yr) with low-density lipoprotein cholesterol levels of > or = 3.36 mmol/l were fed each of 4 diets in randomized order for 6 wk/phase. All food and drink were provided. Diets contained 25 g soy or common sources of animal protein/4.2 MJ containing trace or 50 mg isoflavones/4.2 MJ. At the end of each diet phase, concentrations of estrone sulfate, estrone, estradiol, testosterone, androstendione, dihydrotestosterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate were measured. In postmenopausal women, concentrations of estrone were higher and its precursor, dehydroepiandrosterone, lower after consuming the soy compared with animal protein diets. There was no significant effect of isoflavones on any of the hormones measured. In older men, dehydroepiandrosterone sulfate concentrations were lower after consuming the isoflavone and higher after soy, compared with the animal protein diets. These data suggest that relatively large amounts of soy protein or soy-derived isoflavones had modest and limited sex-specific effects on circulating hormone levels.
Chemopreventive property of a soybean peptide (lunasin) that binds to deacetylated histones and inhibits acetylation.
Cancer Res. 2001 Oct 15;61(20):7473-8.
Lunasin is a unique 43-amino acid soybean peptide. These results point to the role of lunasin as a new chemopreventive agent that functions possibly via a chromatin modification mechanism.
saw palmetto for prostate
5-htp for serotonin
coq10 or coenzyme q10
bean information
Isolated soy protein
Soy Protein Questions
Q. I've read (on the Internet, of course
) that too much soy protein can reduce a man's testosterone levels. Has this been shown to be true in any reasonably conducted study or is this just one more Internet myth?
A. High amounts of soy protein or soy isoflavones do influence hormone levels but not in a significant amount. It is best to not overeat from one food group and have a balance of different foods. Individuals in Asia have been consuming high amounts of soy with no practical influence on their virility or fertility. I don't think one needs to worry about this interaction.
Q. I receive a newsletter called "Health and Age." In it, there is a link to an article putting down soy. I'd like to know your opinion. I do eat lots of soy and drink soymilk. My wife makes fresh soymilk herself every other day. We are both in excellent health (I'm 56, she is 54). So, I feel knocking soy is done, again, by those who aren't fans of alternative ways of living a healthy lifestyle.
A. There are lots of opinions on soy and soy protein. As long as soy is not used in excess, a reasonable amount is safe. Just use soy, as with any food, in moderation. Most foods has the potential to become unhealthy when used in excess.
Q. Does soy sauce have health benefit, too?
A. Yes, it does. See soy sauce for more information.
Q. Dear Dr. I found your article about cholesterol very interesting. I have to agree with you on almost all accounts. My only concern is your promotion of soy as a healthy food source. I believed all the hype about soy and so began using a soy supplement along with soy milk in the morning. At first I felt like it was really helping me. Over a period of time, almost a year, my health started taking a drastic change for the worse. After going to the doctors, I discovered that I had developed Hashimoto's, osteoporosis, and something called hemagglutinin. My cholesterol had gone up, and my cognitive skills had gone down! I was healthy to began with. I only started using soy because I had heard how good it was for you. I'm 53 years old, I regret the day I started using soy. NONE of these conditions were apparent prior to using soy. With much research, I have discovered that my story is identical to many many others. Please research more about soy before promoting it. It's all about big business.
A. Soy is not an unhealthy food just as water is not an unhealthy fluid. But misuse or overuse of any fluid or food has the potential to cause harm.
Q. I really enjoyed reading the info on your website about soy protein. I'm hoping that you can help me with a question about soy protein. My husband and I have been vegetarians for about 20 years. Currently, we rely
very heavily upon soy protein to meet our protein needs. We are both very healthy and very much enjoy soy protein products. I've just recently become aware of the popularity of whey protein (particularly for body builders). It's very hard to find unbiased comparisons of the two. Most of the information that I've found comes from very biased sources or sources which are unqualified to make definitive statements. I'm not asking you to tell me which one is better. I would just like to find some good data. I work as a research administrator so I value
information collected through scientific means.
A. This is a good question and I would like to answer it by posing another question. Which is better, an apple or an orange? My overall philosophy in diet is to try to consume a variety of foods. Thus, my suggestion would be to have some of both soy protein and whey protein rather than having too much of just one. There have not been any studies that I am aware of testing soy protein versus whey protein for long term health maintenance.
Q. I found your pages when I was trying to find info on soy protein isolate. I wonder if you can answer my question, which is still unanswered despite my efforts. I am trying to find out whether soy protein isolate is extracted from raw soybean material, or whether the soybeans are cooked before the extraction.
A. We don't know since we don't get involved in the manufacturing process of soy protein, we are more interested in the clinical effects and clinical research on soy protein. But this is a good question.
Q. I'm wondering about all of the research about soy being bad. Personally I love soy milk, but I'm constantly told by coworkers that it's not good to drink. I'm wondering if you've read any of the research against soy and what you feel is best.
A. Soy products are a healthy addition to one's diet when done so in reasonable amounts and as part of a healthy diet with a variety of other legumes, cereals, fruits, nuts, vegetables, fish, etc. However, excess soy milk may not be the best option for a healthy diet if it ends up providing lots of calories and takes the place of other healthy food options. Furthermore, much of the soy milk sold is sweetened with sugar which is harmful. I think a few ounces of soy milk is healthy to drink, and you could purchase the unsweetened variety and add a few drops of stevia clear liquid to sweeten it without extra calories.
Q. I appreciate very much your research into various nutrients and making it available to the public; however, concerning your recommendation to take soy, have you ever seen this website: xxxxxxxxxxxxxxxxxxx
For the sake of those you are advising to use soy, you might want to take a serious look at it.
A. Thank you for your email. Based on all the information we have read on soy from multiple research studies from a number of different sources, the moderate use of soy products as part of an overall healthy diet that has a wide variety of foods appears to offer no harm, and perhaps offer benefits. If soy were so dangerous as this website makes it seem, then why do Japanese have one of the highest longevity rates in the world yet they have a higher consumption of soy products than other countries?
Q. In your newsletter you mention using soy protein for building muscle. Recently, however, I read some information about soybeans that caused me to ELIMINATE ALL soy products from my diet with the exception of soybean oil. Apparently, soybeans are loaded with phytoestrogens which have moderately strong estrogenic acitivity in the body. While this might be good for a menopausal woman, I don't think it should be introduced into an aging male's body. One article claimed that soybeans were consumed in quantity by Chinese monks as a way of eliminating their libidos! There was also some recent study that showed that consumption of the soybeans (but not the oil) actually reduced the male participants' testosterone levels by 15%! Needless to say, that is the LAST thing I want happening in my aging body. I have since gone over my diet and also eliminated garbanzo beans (also known as "chick peas") because they too have some of the same estrogen-like isoflavones as found in soybeans.
A. See the answer above, Soy, or soy protein, when used in moderation as part of an overall healthy diet which includes a wide variety of foods, is a positive addition to one's diet.
Q. I realize the Japanese people have been eating it for some time. However, I have read that their (true) version of soy is very much different than what the American people consume, thanks to Monsanto. Monsanto owns the bulk of the soy harvest here and has genetically modified our soy so they can spray the crop with Roundup - and the soy plants will not die. Frankensoy is not something I'm going to consume.
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