Vitamins & Supplements Archive

Vitamin D's primary function is to help the body absorb calcium, though it may also protect against prostate cancer and other diseases. Many people do not get enough from sunlight, its natural source, and should get the needed amount via a supplement.

Q: A friend recently recommended that I take the herb ginkgo biloba to protect against getting dementia. Is it effective, and is it safe?

A: The first thing you should consider is that the FDA doesn't regulate the manufacture of any herbal remedy, so the purity and potency of the ginkgo biloba you buy hasn't been checked.

Recently, news stories reported that studies found that daily calcium and vitamin D supplements may not help older women protect their bones or prevent colon cancer — at least not as much as we thought they would.

Researchers for the Women's Health Initiative (WHI) looked at more than 36,000 healthy women ages 50–79. Half of the women took 1,000 mg of elemental calcium and 400 IU of vitamin D each day. The other half took a sugar pill (placebo). After seven years, the women taking the supplements showed slightly better bone density in their hips. They also had fewer hip fractures, but the results could have occurred by chance: Protection against hip fractures, a key goal of improving bone density, was not proven.

When it comes to fighting high blood pressure, the average American diet delivers too much sodium and too little potassium. Eating to reverse this imbalance could prevent or control high blood pressure and translate into fewer heart attacks, strokes, and deaths from heart disease.

Normal body levels of potassium are important for muscle function. Potassium relaxes the walls of the blood vessels, lowering blood pressure and protecting against muscle cramping. A number of studies have shown an association between low potassium intake and increased blood pressure and higher risk of stroke. On the flip side, people who already have high blood pressure can significantly lower their systolic (top number) blood pressure by increasing their potassium intake when they choose to eat healthy foods.

By now, nearly everyone has heard of the health benefits of the omega-3 fats found in fish. The most persuasive studies show that they protect against the serious — and sometimes fatal — episodes of an irregular heart rhythm that can cause sudden death. Other research indicates that a diet rich in omega-3 fats may lower your risk for heart attack and stroke.

Farm-raised salmon is one of the better sources of omega-3s. A 6-ounce serving contains about 3½ grams which is much more than in other popular fish. There's no straight answer to whether farm-raised or wild salmon has more omega-3 fat—it depends on what they eat. Today about half of the salmon sold worldwide comes from fish farms.

In December 2003, the U.S. Food and Drug Administration announced it was banning the sale of products containing ephedra. This announcement heralded the first time the agency has banned an herbal supplement. Its decision was based on extensive research involving more than 16,000 reports of adverse health effects from products containing ephedra. These studies clearly indicate that ephedra is dangerous. And it can kill. Roughly 155 deaths have been blamed on the amphetamine-like stimulant, including the 2003 death of 23-year-old Baltimore Orioles pitcher Steve Bechler.

Ephedra occurs naturally in the Chinese herb ma huang and contains ephedrine and pseudoephedrine, stimulants that can constrict blood vessels. In low doses, they act as decongestants, but in higher doses, they can raise blood pressure. The stimulant effect contributes to the herb's effectiveness as an appetite suppressant, especially when combined with caffeine, aspirin, or both. Its claims for promoting weight loss as well as for increasing energy and alertness led athletes and average gym goers alike to take ephedra products.

After the death of Baltimore Orioles pitcher Steve Bechler more than 10 years ago, many questions arose about the safety of ephedra and the government's role in regulating the herb. Bechler died of heat stroke while taking ephedra, which occurs naturally in the Chinese herb ma huang. The speed-like drug contains the chemical ephedrine, an amphetamine-like compound closely related to adrenaline. Athletes and average people alike started taking ephedra when word started spreading about its ability to aid weight loss and increase energy and alertness.

But just because a supplement comes from natural sources doesn't make it safe. Ephedra can cause a quickened heartbeat and elevated blood pressure. Side effects include heart palpitations, nausea, and vomiting. More than 800 dangerous reactions have been reported with use of the herb. These include heart attacks, strokes, seizures, and sudden deaths. According to a study in the Annals of Internal Medicine, ephedra products make up only 1% of herbal supplement sales in the U.S., but they are responsible for 62% of herb-related reports to poison-control centers.

A recent study published in the New England Journal of Medicine offers another important reminder on careful use of herbal remedies. This caution is rooted in the absence of strict pharmaceutical controls in the manufacture of such products and how the lack of these requirements can leave room for tragic errors.

In the mid-1990s, doctors at a clinic in Belgium treated 43 patients with end-stage kidney failure, requiring dialysis or transplant. Not surprisingly, these individuals had something in common in their medical histories. Between 1990 and 1992, each had used a Chinese herbal remedy in combination with two other drugs for weight loss. The herbal preparation supposedly contained Stephania tetrandra and Magnolia officinalis. But the sudden appearance of kidney failure in these patients, caused their doctors to suspect that the herb Aristolochia fangchi, which is poisonous to the kidneys, had unintentionally been substituted for S. tetrandra. The Chinese names for A. fangchi and S. tetrandra sound similar and the two are often confused. Analysis showed that the herbal remedy did, in fact, contain aristolochic acids, which are derived from A. fangchi. Aristolochic acids cause cancer in rats and mutations in bacteria and mammals.

Reports of patients who had developed urothelial carcinoma (cancer of the tissues lining the bladder, ureter, and part of the kidney), as well as kidney failure related to the Chinese herbs, drew concern among the Belgian doctors. When one of their patients also developed this cancer, the doctors decided that all patients with end-stage kidney failure related to the use of Chinese herbs should be checked for cancer of these organs. By removing these organs, the doctors hoped to prevent cancer from developing in their patients. Thirty-nine of the 43 patients agreed to undergo the preventive surgery. Of these patients, 46% of them already had cancerous growths in the removed tissues. In addition, 19 of the remaining 21 patients had abnormal growths in the urinary system. The investigators also analyzed DNA samples taken from the kidneys and ureters of each patient. The DNA samples for every patient showed changes typically found after exposure to aristolochic acid. The researchers compared these results to analysis of DNA samples taken from eight patients with end-stage kidney failure unrelated to Chinese herbs. None of these control samples showed DNA changes formed by aristolochic acid.

The doctors calculated the cumulative dose of the implicated herb and other treatments for each patient. They found that the risk of cancer was related to the cumulative dose of A. fangchi. Because many of the patients had also taken appetite suppressants as well as a diuretic, the doctors noted that these drugs might enhance the toxicity of aristolochic acid.

This case study provides strong evidence suggesting a relationship between the Chinese herb A. fangchi and urothelial carcinoma. While a manufacturing mistake led to the introduction of this herb into an herbal preparation for weight loss, this study highlights the risks involved in taking herbal remedies. There is little control over the quality of herbal medicines. This means that the label on an herbal medicine may not accurately represent what is actually in the container, as was the case with S. tetrandra. Several countries have banned the use of herbs that contain aristolochic acid, yet Aristolochia is readily available in the United States in capsule form.

In the United States, the FDA does not have the authority to assess the safety and efficacy of a dietary supplement before it reaches the shelves of stores. The agency is allowed to restrict a supplement only after it proves the substance is harmful as commonly consumed, but there is no adequate system for reporting serious side effects associated with these products. Furthermore, the FDA does not have any way of knowing which herbal remedies contain harmful substances such as aristolochic acid. The case of the Chinese herbal diet pill and its association with urothelial cancer is just one of a number of cases that demonstrate the need for greater oversight of dietary supplements and caution in the use of supplements on the part of consumers.