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Literature Review & Commentary

by Alan R. Gaby, MD

 

Magnesium oxide, hypertension, and quality of life

Eighty-three patients with mild hypertension, none of whom had previously been treated with antihypertensive medication, were randomly assigned to receive placebo or magnesium (approximately 200 mg/day of elemental magnesium in the form of magnesium oxide) for 12 weeks, in double-blind fashion. After 12 weeks there was a significant reduction in systolic blood pressure in the magnesium group compared with the placebo group. Magnesium had no effect on diastolic blood pressure.

Analysis of a quality-of-life questionnaire revealed improvements in various measures of quality of life in the magnesium group, compared with the placebo group. These included a reduction in the frequency of chest pain, an increase in physical activity, and better respiratory function, alertness and emotional behavior.

COMMENT: It is noteworthy that the improvements reported in this study were achieved by supplementing with a relatively small amount of magnesium oxide. Many practitioners refuse to prescribe magnesium oxide, because of a belief that it is poorly absorbed. Since magnesium oxide is far less expensive than other commercially available magnesium preparations, its use as a supplement should perhaps be reconsidered.

Borrello G, et al. The effects of magnesium oxide on mild essential hypertension and quality of life. Curr Ther Res 1996;57:767-774.

Hepatitis C, liver cancer, and licorice

A retrospective study was performed to evaluate the effect of long-term administration of Stronger Neo-Minophagen C (SNMC; an intravenous glycyrrhizin preparation) in patients with hepatitis C. Of 453 patients diagnosed with chronic hepatitis C, 84 (Group A) had been treated with SNMC (100 ml/day for 8 weeks, then 2-7 times a week for a median duration of 10.1 years). Another group of patients (Group B) could not be given SNMC, because of the lack of availability of home health care professionals. After 10 years, the cumulative incidences of hepatocellular carcinoma (HCC) for Groups A and B were 7% and 12%, respectively. After 15 years, the cumulative incidences were 12% and 25%, respectively.

COMMENT: SNMC is a product used in Japan that contains 0.2% glycyrrhizin (a component licorice), 0.1% cysteine and 2.0% glycine in physiologic saline. Glycine reportedly prevents the aldosterone-like action of glycyrrhizin, and cysteine has been found to have an antiallergic and detoxifying effect. Glycyrrhizin has antiviral effects and has been shown to prevent the development of certain forms of cancer in animals. The present study suggests that long-term treatment with SNMC prevented the development of liver cancer in patients with chronic hepatitis C.

As SNMC has not been approved by the FDA, the product is difficult to obtain in this country. It is possible that orally administered licorice extract might also be effective. However, because administration of glycyrrhizin can raise blood pressure, deplete potassium, or cause other problems, its use should be monitored closely.

Arase Y, et al. The long term efficacy of glycyrrhizin in chronic hepatitis C patients. Cancer 1997;79:1494-1500.

Prescription drugs: more dangerous than they appear

A random sample of 100 general practitioners practicing in the Bordeaux region of France was surveyed in relation to adverse drug reactions they had observed. Eighty-one doctors agreed to record during three non-consecutive working days any effect they believed to be associated with drug use. The types of effects and the drugs suspected were compared to spontaneous reports received from general practitioners by the Bordeaux pharmacovigilance center. The number of suspected adverse drug reactions per doctor per day was 1.99. The estimate of the under-reporting coefficient (U) was 24,433, which indicates that, as a whole, general practitioners might be expected to report only 1 out of every 24,433 adverse drug reactions.

COMMENT: A random journey through the Physicians" Desk Reference underscores the fact that most drugs are poisons which happen to have a few beneficial side effects. The results of the present study suggest that many prescription drugs are even more dangerous than they appear, because doctors rarely report side effects to the appropriate authorities. On the other hand, millions of Americans already know that they have been harmed by one or more prescription drugs. That is one of the main reasons that so many people are seeking safer alternatives, and that more and more physicians are beginning to embrace natural medicine.

Moride Y, et al. Under-reporting of adverse drug reactions in general practice. Br J Clin Pharmacol 1997;43:177-181.

Glutamine for the critically ill

Eighty-four critically ill patients in an intensive care unit (ICU) who were unable to receive enteral nutrition were randomly assigned to receive a glutamine-containing parenteral nutrition formula or an isonitrogenous, isoenergetic control formula. Survival at six months was significantly greater in patients receiving glutamine than in those receiving the control formula (57% vs 33%; p = 0.049). In glutamine recipients, the total ICU and hospital cost per survivor was reduced by 50.7%, compared with patients receiving the control formula.

COMMENT: Glutamine is often considered a "non-essential" amino acid, because it can be synthesized in the body. However, under conditions of extreme biochemical stress (such as surgery, trauma, or critical illness), the need for this nutrient exceeds the body"s capacity to synthesize it. Critical illness is often associated with low plasma concentrations of glutamine. A deficiency of this amino acid can result in impaired immune function, as well as a breakdown of the normal gastrointestinal lining. The present study indicates that glutamine supplementation of critically ill patients increases survival and reduces hospital costs.

Griffiths RD, et al. Six-month outcome of critically ill patients given glutamine-supplemented parenteral nutrition. Nutrition 1997;13:295-302.

DHEA, menopause, and questionable conclusions

Serum concentrations of dehydroepiandrosterone sulfate (DHEA-S) were measured in 29 patients with premature ovarian failure and in age-matched menstruating controls. The mean serum concentration of DHEA-S was 25% lower in patients than in controls. Because the difference was not statistically significant, the authors concluded that premature ovarian failure does not affect serum DHEA-S levels.

COMMENT: In women, the ovary is responsible for somewhere between 10 and 30% of total DHEA production (the rest is made by the adrenal gland). DHEA supplementation of postmenopausal women has been shown to enhance certain parameters of immune function and to prevent bone loss. In addition, some postmenopausal women report that taking DHEA improves their overall sense of well-being. These observations strongly suggest that menopause (or premature ovarian failure) results in a decline in DHEA levels (at least in some women). The authors of the present study are incorrect when they claim that ovarian failure does not reduce DHEA-S levels. In fact, in their study, the levels declined by an average of 25%. Although there is more than a 5% probability that this reduction was due to chance, it is wrong to conclude that there was no decline. Other studies have shown that DHEA(S) levels do fall significantly around the time of menopause. A growing body of evidence suggests that DHEA replacement therapy may be appropriate for many postmenopausal women.

Elias AN, et al. Serum levels of androstenedione, testosterone and dehydroepiandrosterone sulfate in patients with premature ovarian failure to age-matched menstruating controls. Gynecol Obstet Invest 1997;43:47-48.

Olives, olive oil and heart disease

2-(3,4-di-hydroxyphenyl)-ethanol (DHPE) is a phenolic component of extra-virgin olive oil that has potent antioxidant activity. In the present study, preincubation of platelet-rich human plasma with DHPE inhibited ADP- and collagen-induced platelet aggregation. A partially characterized phenol-enriched extract obtained from the aqueous waste from olive oil was also a potent inhibitor of platelet aggregation.

COMMENT: There is evidence that individuals who consume a Mediterranean diet have a reduced risk of developing heart disease. Olive oil, a component of the Mediterranean diet, is believed to be one of the protective factors. Olive oil is rich in oleic acid, a monounsaturated fatty acid which has been found to inhibit the oxidation of LDL cholesterol. However, the present study demonstrates that there is at least one other compound in olive oil (and another substance in whole olives) that might prevent heart disease by a different mechanism. Therefore, it is unlikely that the purported cardioprotective effect of olive oil could be duplicated by other high-oleic-acid foods, such as the specially made high-oleic-acid sunflower oil that is currently being studied by nutrition scientists.

Petroni A, et al. Inhibition of platelet aggregation and eicosanoid production by phenolic components of olive oil. Thromb Res 1995;78:151-160.

Unusual cases of diarrhea

Two patients with lactase deficiency who were being treated for Graves" disease consistently developed severe diarrhea after ingestion of an antithyroid drug (methimazole plus propylthiouracil) that contained lactose as a carrier. The close temporal relationship between ingestion of the lactose-containing tablets, as well as the absence of side effects following ingestion of lactose-free methimazole tablets, suggested that lactose was the cause of the diarrhea.

COMMENT: In considering medication side effects, there is a tendency to overlook the "inert" ingredients in tablets and capsules. However, the various coloring agents, fillers and binders found in medications may cause significant reactions in susceptible individuals. One might wonder how the small amount of lactose present in a pill could trigger severe diarrhea, even in someone with lactose intolerance. While maldigestion of lactose could conceivably account for the symptoms, allergy may also be involved. There is a high correlation between lactose intolerance and milk-protein allergy. It also has been shown that commercial-grade lactose contains a small amount of a sugar-protein complex (presumably a glycosylated milk protein), which might be capable of provoking symptoms in milk-allergic individuals.

Petrini L, et al. Lactose intolerance following antithyroid drug medications. J Endocrinol Invest 1997;20:569-570.

Ear candles ineffective

Ear candles are used by some alternative health care practitioners primarily for removal of cerumen. The hollow candle is placed in the external auditory canal and a flame is lit at the opposite end. The lighted candle is thought to create a vacuum, which draws cerumen and other impurities from the ear canal.

In the present study, tympanometric measurements in an ear canal model demonstrated that ear candles do not produce negative pressure. A limited clinical trial (eight ears) showed no removal of cerumen, and candle wax was actually deposited in some ears. A survey of 122 otolaryngologists identified 21 ear injuries resulting from the use of ear candles.

COMMENT: If effective, ear candles could be used as a low-cost alternative to cerumen removal in a doctor"s office. However, the current study raises questions about the safety and efficacy of this procedure. I would welcome comments from readers who have had a more favorable experience with ear candles.

Seely DR, et al. Ear candles - efficacy and safety. Laryngoscope 1996;106:1126-1129.


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