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Resveratrol and bone density
Taurine and heart failure
Potassium intake lowers stroke risk
Veggie diet plus fish cuts colon cancer risk
Reader question: vitamins and dark urine
General Information

Resveratrol and bone density

Resveratrol is a non-essential antioxidant phytonutrient that offers important health benefits, including an anti-inflammatory effect. It is found in red grapes, cranberries, blueberries, and peanuts, and is commonly known for its presence in red wine. In grapes it is mostly in the skin. Resveratrol is also available in dietary supplements. It protects the brain, and has an anti-aging effect because of its protection of telomere length. Telomeres are the end sections of chromosomes that shorten with cell division, a process associated with aging.

New research shows that resveratrol also improves bone density, particularly in men with metabolic syndrome (a collection of symptoms and lab tests including obesity, high blood lipids, high blood sugar, and high blood pressure). Danish researchers evaluated 74 middle-aged men (average age 49.3 years) with metabolic syndrome. They gave some a daily dose of 150 mg of resveratrol, some 1000 mg, and some a placebo. They treated them for 16 weeks.

They measured an enzyme associated with bone formation (bone alkaline phosphatase, or BAP), as well as bone mineral density of the lumbar spine and hip. During and at the end of the study, BAP increased significantly in the group on the high dose of resveratrol compared with the placebo group. In addition, the bone mineral density in the spine increased significantly in the high dose resveratrol group. The changes in both BAP and bone density corresponded to each other. No changes were detected in the hip. The researchers concluded that resveratrol supplementation improved both bone matrix formation and mineralization.

Practical guidelines:

Resveratrol is valuable in many ways. You can get some from red wine, but to get therapeutic levels, it is probably safer to take supplements. You can also get some by eating red or purple grapes, berries, and peanuts or peanut butter, but this is unlikely to reach the doses in this study. Supplements from 25 to 500 mg are available, mostly derived from Japanese knotweed.

Taurine and heart failure

Taurine is a sulfur-containing amino acid that is not incorporated into proteins and is structurally different from other amino acids. It is an important component of bile, acts as an antioxidant, and stabilizes membranes. It is essential for cardiovascular function as well as other muscle and nerve function. Studies have also shown its value in preservation of retinal function. It is the most abundant free amino acid in the heart, retina, skeletal muscle, brain, and white blood cells.

A study from researchers in Iran shows that taurine is valuable in heart failure. They did a placebo-controlled study on 29 patients with low ejection fraction (EF, the proportion of blood in the ventricle that is pumped out with each heartbeat). Their average age was 60.5 years. All of the subjects had an EF below 50 percent, with normal being 55 to 70 percent. Their average EF was 29 percent. They were all in New York Heart Association functional class II (mild symptoms such as slight shortness of breath) or III (marked limitation in activity). A total of 15 of them were then treated with taurine supplements of 500 mg three times per day, and the other 14 received a placebo.

This was a short study of only two weeks, but still in those receiving the taurine, their exercise time, metabolic output, and exercise distance significantly increased, while their blood pressures went down. Exercise time went from 7.3 to 10 minutes (a 36 percent increase), exercise distance went from 602 to 804 meters (a 33 percent increase), and metabolic output (METS) went from 6.3 to 8. No changes were noted in the placebo group. (Beyranvand MR et al., Effect of taurine supplementation on exercise capacity of patients with heart failure. J Cardiol. 2011 May;57(3):333-7.)

Practical guidelines:

This is a relatively low dose of taurine (some studies have used 2000 to 6000 mg per day for treatment of congestive heart failure), and it was for a very short time. Still the results were very good, and likely to have continued to improve with longer treatment or a higher dose, or both. I take 2000 mg of taurine daily, and it is readily available in 500 mg capsules.

Potassium intake lowers stroke risk

Adequate potassium in the diet helps to reduce the risk of stroke. Potassium is abundant in fresh fruits, vegetables, and legumes. Dietary recommendations are 3500 mg (World Health Organization) to 4700 mg per day (USDA). This is easily achieved with the right dietary selections on the high end of the 5 to 9 serving recommendation for fruits and vegetables. For example, one average baked potato has 926 mg, one cup of cooked spinach has 839 mg, a cup of white beans has 1004 mg, and a cup of cubed acorn squash has 899 mg, and an average avocado has 975 mg. One cup of mashed banana has 806 mg (and banana is the standard recommendation for people who need potassium (for example if they are taking potassium-wasting diuretics), but it is not the only good source (perhaps just the most commonly available). These six food servings that I just listed provide 5400 mg of potassium. Nuts and citrus fruits are other good sources.

In a recent study of the Women’s Health Initiative, 90,137 postmenopausal women from 50 to 79 years old were free of stroke history at the start of the study and were followed for an average of 11 years. The researchers were looking for total strokes, ischemic and hemorrhagic strokes, and all-cause mortality, and relating the risk of those conditions to dietary potassium intake. They divided the subject population into quarters from the lowest to the highest intake. The overall average potassium intake was 2611 mg per day.

For those subjects in the highest quarter of potassium intake the risk of all-cause mortality was reduced by 10 percent (highly significant with such a large subject population). The risk of ischemic stroke was reduced by 16 percent. No association was found with hemorrhagic stroke. In women without hypertension, those with the highest potassium intake had a 27 percent lower risk of stroke compared to those with the lowest intake. (Seth A, et al., Potassium intake and risk of stroke in women with hypertension and nonhypertension in the Women's Health Initiative. Stroke. 2014 Oct;45(10):2874-80.)

In this study population, only two percent of the subjects met or exceeded the USDA recommended intake of 4700 mg per day. Even with the lower standard of the WHO, only 16.6 percent of the women met or exceeded that. This does not establish a cause and effect relationship between potassium intake and stroke, just a correlation. Even after controlling for other variables, potassium might just be a marker for fruit, vegetable, and legume intake, and these have many other benefits such as vitamins, minerals other than potassium, phytochemicals, and fiber, all of which might reduce the risk for stroke.

Practical guidelines:

For numerous reasons it is important to eat a diet rich in whole, minimally processed, fresh fruits, vegetables, and legumes. Limiting salt intake will help reduce excessive excretion of potassium (dietary salt leads to higher water intake, washing out potassium and other minerals in the urine).

Potassium supplement doses are limited to 99 mg without a prescription because they are often harsh on the stomach lining, potassium chloride in particular, although this is sold as a substitute for table salt. It is easy to get a safe source of potassium through diet, and if you need extra, a serving of organic salt-free vegetable juice will safely provide 600 mg of potassium, almost as much as the prescription sources.

Veggie diet plus fish cuts colon cancer risk

The research is strikingly one-sided when it comes to the health value of vegetarian diets. Some people are strict vegans, some are lacto-ovo vegetarians who eat eggs and dairy products with their vegetarian foods, and some are not strictly vegetarian, but eat a mostly vegetarian diet with some fish (often referred to as pesco-vegetarians) and may also include dairy or eggs. All of these choices are apparently far superior for overall health and prevention of chronic degenerative disease than an omnivorous diet (and any diet of unprocessed, whole, natural foods is better than eating junk instead of food).

In a new study of 77,659 subjects in the Adventist Health Study 2, men and women were recruited from January 2002 to December 2007, and then followed until the end of 2014. The researchers used a validated food frequency questionnaire to categorize the subjects as vegan, lacto-ovo vegetarian, pesco-vegetarian, semi-vegetarian, and non-vegetarian. They then evaluated the relationship of dietary patterns to the incidence of cancer of the colon and rectum.

Over the 7.3 years of the study, they identified 380 cases of colon cancer, and 110 cases of rectal cancer. The combined vegetarian subjects had a 22 percent lower incidence for all colorectal cancers compared to the non-vegetarians. This included a 19 percent risk reduction for colon cancer and a 29 percent reduction for rectal cancer. After adjustment for other variables, the risk reduction for colorectal cancer for vegans was 16 percent. For lacto-ovo vegetarians it was 18 percent. For the pesco-vegetarians the results were the best with a 43 percent risk reduction compared to non-vegetarians. Semi-vegetarians had only an 8 percent risk reduction compared to non-vegetarians. (Orlich MJ, et al., Vegetarian dietary patterns and the risk of colorectal cancers. JAMA Intern Med. 2015 Mar 9. doi: 10.1001/jamainternmed.2015.59. [Epub ahead of print]

Population studies such as this do not show cause and effect, but the consistency of these results with past studies makes a strong case. In 2005, a study of 478,040 men and women followed for 4.8 years showed a positive relationship of meat intake to the development of colorectal cancer, and an inverse relationship to fish intake. (Norat T, et al., Meat, fish, and colorectal cancer risk: the European Prospective Investigation into cancer and nutrition. J Natl Cancer Inst. 2005 Jun 15;97(12):906-16.)

In a large British study of 61,647 men and women, 32,491 were meat eaters, 8612 were fish eaters, and 20,544 were vegetarians (of which 2246 were vegans). Compared to meat eaters, the risk of stomach cancer for fish eaters was 38 percent lower, and for vegetarians it was 63 percent lower. For colorectal cancers, the risk for fish eaters was 34 percent lower. Surprisingly, and contrary to other studies, in this report vegetarians did not have an advantage for colorectal cancers. For blood and lymphatic cancers, fish eaters had just a 4 percent lower risk than meat eaters, but vegetarians had a 36 percent lower risk. For multiple myeloma, a bone marrow cancer, fish eaters had a 23 percent lower risk than meat eaters, and vegetarians had a 77 percent lower risk. Key TJ, et al., Cancer in British vegetarians: updated analyses of 4998 incident cancers in a cohort of 32,491 meat eaters, 8612 fish eaters, 18,298 vegetarians, and 2246 vegans. Am J Clin Nutr. 2014 Jul;100 Suppl 1:378S-85S.)

Practical guidelines:

Choose a diet that is rich in fresh fruits and vegetables, legumes and whole grains, seeds, and nuts. If you choose to include animal products in your diet, fish would be the best first choice, and try to make sure that you select wild fish from clean waters to avoid the hormones and antibiotic residues found in farmed fish or contaminants from pollution, such as mercury (especially problematic in larger fish, such as tuna). A recent article in the New York Times discusses “The Myth of High Protein Diets,” written by Dr. Dean Ornish. It is well worth reading, and found at this link:

Reader question: vitamins and dark urine

The following question came from a reader of my website:

Taking supplements often results in very dark-colored urine. I get the feeling that the supplement is going right through my body and think as a result that it’s not having any benefit. What are your comments to this? With natural food, e.g. grapefruit, this does not occur!

This is a common question I have answered over the years, along with the one about the excretion of these nutrients creating “expensive urine” rather than doing us any good. These are my answers:

Vitamin B2 is also known as riboflavin. The “flavin” part of the word is from the latin for yellow, and it refers to the bright fluorescent yellow color of the vitamin. When you absorb it from the intestine, any extra beyond basic needs is safely excreted in the urine. If you take supplements, you are almost certainly going to absorb enough B2 to excrete some, and the extra makes the urine a deeper yellow than usual. If you have dark amber or brown urine, this might be from a medical condition (liver or blood disease, for examples) or from medications, and you should ask your doctor to check that. If you do not drink enough water, the urine will also be darker, and this is easily remedied. Water consumption comes not only from drinking, but also from fruits, vegetables, teas, and coffee (although caffeine is also a diuretic, increasing urine output). Most foods (including grapefruit) do not have a high enough concentration of riboflavin to alter urine color.

Many things are excreted in the urine, including much of the water that you drink, medications that you take, and non-medicinal drugs (for which they test athletes’ urine). Also, much of what you eat is excreted in the stool, such as all the fiber that is in your diet. This does not mean that you do not need to consume any of these.

Many water-soluble vitamins are excreted when taken in common supplemental doses. This has led some skeptical authorities to claim that supplement takers “have the most expensive urine in the world.” This comment ignores the fact that most of the water-soluble supplements are incredibly cheap (and incredibly safe, unlike the expensive drugs that are also excreted). Expensive supplements do exist, but they are not usually the ones that are so readily excreted. All of this discussion ignores the more important issue: whether you excrete a vitamin or not is not as important as what it does on the way through the body.

For example, vitamin C has many functions, and it is likely that it protects the body from infection, inflammation, cancer, and heart disease while it is circulating around and saturating tissues. The amount that you absorb that is then excreted in the urine has to bathe the tissues on its way through, especially the kidneys, ureters, bladder, urethra, and this may well have beneficial effects, such as reduction of inflammation and infection.

Of course, the most critical issue is the published medical research that analyzes the effect of specific doses of specific supplements. As I have frequently reported, dietary supplements of many kinds have documented benefits in doses that often do lead to urinary excretion. Read back through my old newsletters (all posted on my website) and you will see reviews of many of these scientific articles. (And even in this issue with articles on resveratrol and taurine.)

Practical guidelines:

I have been taking relatively large doses of dietary supplements for 45 years (I did not learn of their potential benefits until after graduation from medical school). If my urine is very yellow, I assume that I have not been drinking enough water (I always eat a lot of fruits and vegetables). Don’t be deterred by skeptical reports or claims of “expensive urine.” Focus instead on the documented reports of benefit from many supplements.

Still, these are supplements, and not meant to be an excuse to indulge in junk or to be a replacement for a healthy diet, which should provide nutrients, both known and unknown, that are not available as supplements. If you have dark urine other than the typical strong yellow of riboflavin, make sure that it is not due to a medical problem or a medication.

General Information


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From September to June, I see patients in New Smyrna Beach, Florida.
Call 386-409-7747, or send an email to to make arrangements.

In summer, I have a variable schedule, and I see patients in offices at the
Rothfeld Center for Integrative Medicine in Waltham, Massachusetts. For appointments, send an email to make arrangements, or call: 386-409-7747.

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Information herein is not medical advice or direction. All material in this newsletter is provided for information only. Its contents should not be used to provide medical advice on individual problems. Consult a health care professional for medical or health advice.