Archive

Health Bits and Pieces
By Michael Janson, M.D.
September 06, 2006

A new literature review shows that consumption of tap water increases the risk of bladder cancer. Researchers evaluated 2729 patients with bladder cancer and 5150 controls in studies done in the United States, Canada, France, Finland, and Italy. On average, people who consumed more than two liters of tap water per day had a 46 percent higher risk of bladder cancer than those who consumed less than a half liter per day, and the risk was 50 percent higher among men. (Villanueva CM, “Total and specific fluid consumption as determinants of bladder cancer risk,” Int J Cancer. 2006 Apr 15;118(8):2040-7.

Chlorine in tap water combines with organic matter to create harmful substances, including trihalomethane (THM). The researchers found that total fluid intake was not associated with any increase in risk, including other sources of water, such as filtered or bottled waters. In this study, THM exposure was independent of the increased risk of bladder cancer, so other contaminants that are carcinogenic must be present. As in some other studies, this research showed a greater risk of bladder cancer associated with coffee consumption. More than five cups a day significantly increased the risk.

Previous studies have shown that THM is an independent risk for bladder cancer. The level of THM in tap waters of developed countries is directly related to chlorination, and cumulative exposure increases the risk (Villanueva CM, et al., “Disinfection byproducts and bladder cancer: a pooled analysis,” Epidemiology. 2004 May;15(3):357-67).

Some medications used to control blood pressure appear to increase the risk of developing adult onset diabetes. In a prospective study from the Nurses' Health Study (NHS) I and II and the Health Professionals Follow-up Study (HPFS) with 75,000 subjects (including 41,193 older women, 14,151 younger women, and 19,472 men), beta-blockers and diuretic drugs (thiazides) led to a 20 to 45 percent higher incidence of diabetes (Taylor EN, et al., “Antihypertensive medications and the risk of incident type 2 diabetes,” Diabetes Care. 2006 May;29(5):1065-70). Other blood pressure medications, such as calcium channel blockers and ACE inhibitors, were not associated with this risk.

Moderate hypertension can usually be controlled with diet, exercise, weight loss, and a number of supplements, including magnesium, coenzyme Q10, vitamin C, fish oil, and garlic, among others. Unless the blood pressure is at crisis levels, it is better to try natural treatments first. Diabetes increases cardiac risks and speeds aging, and managing blood pressure naturally also reduces cardiac risks and slows the aging process.

Although some nutritionally-oriented physicians recommend against consumption of soy, the evidence for its health benefits continues to accumulate. Among 483 women undergoing angiography for coronary artery disease, those with the highest level of daidzein, a soy isoflavone similar to genistein, had lower triglyceride levels and a higher HDL-cholesterol (Bairey Merz, CN, et al., “Phytoestrogens and lipoproteins in women,” J Clin Endocrinol Metab. 2006 June;91(6):2209-2213.) Isoflavones have mild estrogenic activity, attaching to estrogen receptors and protecting tissues from the effects of stronger estrogens.

Soy food consumption has also been associated with lowering lipid levels and improvement in kidney function in diabetics. In a crossover study, nephropathy patients with low protein intake were first fed a diet with 70 percent of the protein from animal sources and 30 percent from vegetable sources for 7 weeks. After a 4-week washout period, they were fed a similarly low-protein diet with 35 percent of the protein from soy and 30 percent from other vegetable sources. Both lipid levels and kidney function improved on the higher soy-protein diet. (Azadbakht L, et al., “Beneficiary effect of dietary soy protein on lowering plasma levels of lipid and improving kidney function in type II diabetes with nephropathy,” Eur J Clin Nutr. 2003 Oct;57(10):1292-4).

In a Chinese study on 21,494 deceased cases and 19,968 controls, total age-adjusted mortality was reduced by 23 percent in men and 34 percent in women among those who consumed soy products four times a week or more, compared to those who consumed it once a month or less. Increasing soy intake was inversely proportional to deaths from lung, colon, stomach, and breast cancers as well as heart disease. (Ho SY, et al., “Soy consumption and mortality in Hong Kong: Proxy-reported case-control study of all older adult deaths in 1998,” Prev Med. 2006 Jul;43(1):20-6.

The carotenoids lutein and zeaxanthin are antioxidants that appear to protect against both age-related macular degeneration (ARMD) and cataract. In a study of serum levels in 899 subjects, compared to those with the lowest zeaxanthin levels, those with the highest levels had a 90-percent reduction in risk of ARMD and a 47-percent reduction in the risk of developing cataracts. Those with the highest lutein levels in the serum had 70 percent reduced risk of ARMD. (Delcourt C, et al., “Plasma lutein and zeaxanthin and other carotenoids as modifiable risk factors for age-related maculopathy and cataract: the POLA Study,” Invest Ophthalmol Vis Sci. 2006 Jun;47(6):2329-35.)

Michael Janson, M.D., is Past President of the American College for Advancement in Medicine and the author of four books, including Dr. Janson's New Vitamin Revolution and the User's Guide to Heart Healthy Supplements. He writes and publishes a free monthly newsletter, Dr. Janson's Healthy Living, available at his website, www.drjanson.com. Dr. Janson does phone and email consults on nutrition, lifestyle, and dietary supplements. He is also a consultant for companies in natural health care. He can be reached at drjanson@drjanson.com.