Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
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2 Stars
Benign Prostatic Hyperplasia
760 mg of a combination of glycine, alanine, and glutamic acid three times per day for two weeks, then 380 mg three times per day
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In one study, supplementing with amino acids reduced urgency, frequency, and delay starting urine flow.
In a controlled trial, men with BPH received a supplement containing three amino acids (glycine, alanine, and glutamic acid) totaling about 760 mg three times per day for two weeks, then 380 mg three times per day for a total of three months. After three months, about half of these men reported reduced urgency, frequency, and/or less delay starting urine flow, compared to 15% or less of the men who received a placebo.1 Another similar controlled trial of this combination also reported positive results2 Although it is not known how the amino acid combination works, it is believed to reduce the amount of swelling in prostate tissue. |
Nutrition experts recommend that protein, as a source of amino acids, account for 10–12% of the calories in a balanced diet. However, requirements for protein are affected by age, weight, state of health, and other factors. On average, a normal adult requires approximately 0.36 grams of protein per pound of body weight. Using this formula, a 140-pound person would need 50 grams (or less than 2 ounces) of protein per day. An appropriate range of protein intake for healthy adults may be as low as 45–65 grams daily. Some athletes have higher amino acid requirements.3 Most American adults eat about 100 grams of protein per day, or about twice what their bodies need and at least as much as any athlete requires.
Supplements of individual amino acids are recommended by doctors for specific purposes, such as lysine for herpes or phenylalanine for pain.
Foods of animal origin, such as meat and poultry, fish, eggs, and dairy products, are the richest dietary sources of the essential amino acids. Plant sources of protein are often deficient in one or more essential amino acids. However, these deficiencies can be overcome by consuming a wide variety of plant foods. For example, grains are low in lysine, whereas beans provide an excess of lysine. It was previously believed that, in order for vegetarians to obtain adequate amounts of protein, all of the essential amino acids had to be “balanced” at each meal. For example, a grain and a bean had to be consumed at the same meal. However, more recent research has indicated that, while consuming a proper mix of amino acids is important, it is not necessary to consume them all at the same meal.4
The vast majority of Americans eats more than enough protein and also more than enough of each essential amino acid for normal purposes. Dieters, some strict vegetarian body builders, and anyone consuming an inadequate number of calories may not be consuming adequate amounts of amino acids. In these cases, the body will break down the protein in muscle tissue and use those amino acids to meet the needs of more important organs or will simply not build more muscle mass despite increasing exercise.
Amino acids include several different nutrients, each of which has the potential to interact with drugs. Look up the unique interactions for each and discuss the potential benefits and risks of your current medications with your doctor or pharmacist before adding amino acids:
Many Western diets provide more protein than the body needs, causing excess nitrogen to be excreted as urea in urine. The excess nitrogen has been linked in some studies with reduced kidney function in old age. Some, but not all studies have found that when people have impaired kidney function, restricting dietary intake of protein slows the rate of decline of kidney function.5
Excessive protein intake also can increase excretion of calcium, and some evidence has linked high-protein diets with osteoporosis,6 particularly regarding animal protein.7 On the other hand, some protein is needed for bone formation. A double-blind study showed that elderly people whose diets provided slightly less than the recommended amount of protein suffered less bone loss if they consumed an additional 20 grams of protein per day.8 A doctor can help people assess their protein intake and needs.
Amino acids include several different nutrients, each of which has the potential for side effects. Look up the unique side effects for each and discuss the potential benefits and risks with your doctor or pharmacist:
1. Damrau F. Benign prostatic hypertrophy: amino acid therapy for symptomatic relief. J Am Geriatr Soc 1962;10:426–30.
2. Feinblatt HM, Gant JC. Palliative treatment of benign prostatic hypertrophy: value of glycine, alanine, glutamic acid combination. J Maine Med Assoc 1958;46:99–102.
3. Lemon P. Is increased dietary protein necessary or beneficial for individuals with a physically active lifestyle? Nutr Rev 1996;54(4 Pt 2):S169–75 [review].
4. Young VR, Pellett PL. Plant proteins in relation to human protein and amino acid nutrition. Am J Clin Nutr 1994;59(suppl):1203S–12S.
5. Sitprija V, Suvanpha R. Low protein diet and chronic renal failure in Buddhist monks. BMJ 1983;287:469–71.
6. Heaney R. Protein intake and the calcium economy. J Am Diet Assoc 1993;93:1259–60 [review].
7. Abelow BJ, Holford TR, Insogna KL. Cross-cultural association between dietary animal protein and hip fracture: a hypothesis. Calcif Tiss Int 1992;50:14–8.
8. Schürch MA, Rizzoli R, Slosman D, et al. Protein supplements increase serum insulin-like growth factor-I levels and attenuate proximal femur bone loss in patients with recent hip fracture. Ann Intern Med 1998;128:801–9.
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ReferencesLast Review: 11-07-2012
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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2013.
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