Altmed Watch

August 1, 2003

The latest research on complementary and alternative medicine

Can CAM therapies actually relieve PMS?

A recent review of the clinical research on several nutritional and botanical interventions offers a qualified "Yes" to that question. Dividing treatments into three groups based on level of evidence to support them, the reviewers gave calcium supplementation (1,200–1,600 mg/day) an A rating because it's supported by large-scale double-blind trials and systematic reviews. Magnesium (400–800 mg/day), vitamin B6 (50–100 mg/day), and caffeine cessation were all judged to probably be effective against PMS because they are supported by lesser quality randomized trials (level B rating). Botanicals receiving the same B rating included chasteberry (4–20 mg/day) and ginkgo (80 mg bid).

Among the PMS remedies receiving the lowest rating (C) because they were only supported by expert opinion, case reports, and uncontrolled studies were herbs like black cohosh and kava, and dietary manipulation. The latter includes cutting back on dairy products, refined sugar, and high-sodium foods, or eating a low-fat, high-fiber diet, which is supposed to help reduce estrogen levels during the luteal phase of the menstrual cycle.

Girman A, Lee R, Kliger B. An integrative medicine approach to premenstrual syndrome. Am J Obstet Gynecol. 2003;188(5 suppl):S56-S65.

New evidence linking fiber and colon cancer

Despite some bad press in recent years, dietary fiber does seem to offer a measure of protection against colon cancer, according to two major reports in Lancet.

One of these observational studies looked at over half a million people in 10 European countries, finding that high fiber intake reduced the risk of colon cancer by 42%, even after adjusting for numerous confounding factors.1 A separate study that looked at the incidence of precancerous lesions in almost 34,000 Americans concluded that a high fiber intake reduced the threat of colorectal adenomas by 27%, with the strongest protective effect coming from grains, cereals, and fruits.2

Comparing these positive results to recent negative studies can help put the data into context: The Nurses' Health Study, for instance, concluded that dietary fiber doesn't protect against colon cancer, but fiber intake was relatively low across the board in this population (9.8 g in the lowest quintile vs. 24.9 g in the highest).3 By contrast, in the European investigation just reported in Lancet, the intakes were 12.6 and 33.1 g, respectively. Even more important were the differences in the intake of cereal fiber, which has been most closely linked to colon health: Among the nurses, the median in the highest quintile was 4.8 g a day, which was about the same as the lowest quintile in the European group (4.7 g).

The main criticism of the recent interventional trials that failed to prove that fiber supplements reduce the risk of colon polyps is the fact that subjects were only followed for 3 to 4 years.4,5 If a low-fiber diet does increase the risk of colon cancer, the pathophysiologic changes it produces in the gut likely take decades to evolve.

1. Bingham SA, Day NE, Luben R, et al. Dietary fibre in food and protection against coloretal cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC): an observational study. Lancet. 2003;361:1496-1501.

2. Peters U, Sinha R, Chatterjee N, et al. Dietary fibre and colorectal adenoma in a colorectal cancer early detection programme. Lancet. 2003;361:1491-1495.

3. Fuchs CS, Giovannucci E, Colditz GA, et al. Dietary fiber and the risk of colorectal cancer and adenoma in women. N Engl J Med. 1999;340:169-176.

4. Schatzkin A, Lanza E, Corle D, et al. Lack of effect of a low-fat, high-fiber diet on recurrence of colorectal adenomas. N Engl J Med. 2003;342:1149-1155.

5. Alberts DS, Martinez ME, Ros DJ. Lack of effect of a high-fiber cereal supplement on the recurrence of colorectal adenoma. N Engl J Med. 2003;342:1156-1162.

A 'natural' approach to diabetic neuropathy

Lipoic acid, a potent antioxidant that's found in many plant and animal foods, can relieve the sensory polyneuropathy that plagues patients with diabetes. When German investigators gave 600 mg of alpha lipoic acid or a placebo intravenously to 120 type 1 and type 2 diabetics over a 3-week period (600 mg/day for 14 treatments), they found the antioxidant produced significant improvements: Compared to placebo, patients experienced marked relief of their stabbing and burning pain, less tenderness upon contact, less paresthesia, and less numbness through sleep. There was no evidence to suggest that the supplement caused any adverse effects. Independent research also suggests that 300 mg of oral lipoic acid, taken in divided doses, may have a similar therapeutic effect. Experts warn, however, that the supplement can lower blood glucose levels, necessitating a dosage adjustment in any hypoglycemic drugs.

Barinov A, Dyck PJ, et al. The sensory symptoms of diabetic polyneuropathy are improved with

-lipoic acid. Diabetes Care. 2003;26:770-776.

Hendler SS, Rorvik D (eds). PDR for Nutritional Supplements. Montvale, NJ: Medical Economics Thomson Healthcare, 2001.

The diet/ovarian cancer connection

A plant-based diet may reduce the risk of ovarian cancer, suggests this case–control study that compared the eating habits of 124 ovarian Ca patients to almost 700 matched controls.

After dividing subjects into five dietary intake levels, investigators found that the highest intake of carotenoid-rich foods reduced the threat of the disease by 67%, while women with the highest total vegetable intake were 53% less likely to develop cancer. Similarly those who consumed the most fiber were 57% less likely to develop the malignancy. But it's worth mentioning that a high intake of grain products per se did not seem to protect women from the cancer, despite the fact that grains are considered a source of fiber. Dietary fiber is found primarily in the bran component of grains, which is removed during processing. And in the western New York population surveyed for this study, consumption of unrefined whole grains is low.

Researchers theorize that diet may contribute to ovarian cancer by modifying endogenous hormone levels. Several previous studies have shown that vegetarians have lower levels of estrone and estradiol, when compared to omnivores. And others have found that these hormone levels can be altered by dietary changes.

McCann SE, Freudenheim JL, Marshall JR, et al. Risk of human ovarian cancer is related to selected nutrients, phytochemicals, and food groups. J Nutr. 2003;133:1937-1942.

Department editor Paul L. Cerrato, MA, Managing Editor of Contemporary OB/GYN, is a guest lecturer at the Institute of Human Nutrition, Columbia University College of Physicians and Surgeons, New York, N.Y.