Nutritional Supplements: 5 Supplements Scrutinized (cont.)


  • It might help people with diabetes control their blood sugar when used with conventional treatment.
  • There is significant improvement in erections with Korean red ginseng -- even rivaling impotence drugs such as Viagra.
  • There are few side effects in healthy people with regular doses of ginseng.


  • It may decrease the effectiveness of the blood thinner Coumadin.

What We Don't Know:

  • The effects of ginseng on the immune system's ability to fight off cancer and infection are uncertain.
  • Cancer effects are unknown but one study showed white ginseng -- but not red -- decreased recurrence of intestinal cancer, while another showed red ginseng powder decreased recurrence of a different type of cancer -- stomach cancer.
  • There is an increased number and activity of infection-fighting immune cells with both Korean and Siberian ginseng, but no evidence of actual decreased infections.
  • There are mixed study results for memory- and energy-boosting abilities with ginseng.

A fair amount of research has been done on ginseng -- looking at many different possibilities -- but so far, very few of them -- if any -- have produced conclusive results.

St. John's Wort

A few years back, St. John's Wort was looking like one herb that might effectively treat a common medical problem -- depression. But as more research was unveiled, a different story unfolded.


  • It is possibly effective in treating mild to moderate depression -- maybe even as effectively as prescription antidepressants and possibly with fewer side effects. However, recent studies show that St. John's Wort is of no benefit in treating major depression of moderate severity. More studies are needed to see whether it really has much antidepressant effect at all.
  • It might help obsessive-compulsive disorder and even severe PMS.


  • It is linked to potentially deadly drug interactions. Researchers discovered that St. John's Wort decreases the effectiveness of some lifesaving drugs -- including cancer chemotherapy drugs, medications to fight HIV infection, and drugs, such as cyclosporine, to prevent organ rejection after a transplant. And a recent study even showed the herb likely interferes with some 50% of all over-the-counter and prescription medications.

Preliminary studies have show that St. John's Wort may work by preventing nerve cells in the brain from reabsorbing the chemical called serotonin, or by reducing levels of a protein involved in the body's immune system functioning. The take-home message so far with this supplement's effectiveness is we really don't know. But we do know it could be potentially very dangerous in anyone taking lifesaving medications.

And always keep in mind that we still know relatively very little about all of these supplements. Don't assume they are natural and harmless. Before venturing out, it's best to discuss these and other supplements with your doctor -- especially if you are on other medications.

Originally published July 26, 2004.

Medically updated August 2005.

SOURCES: WebMD Medical News: "Glucosamine Ups Ibuprofen's Pain Relief." WebMD Medical News: "Glucosamine Stops Knee Arthritis in Women." WebMD Medical Reference in collaboration with The Cleveland Clinic: "Dietary Supplements for Treatment of Arthritis." WebMD Medical News: "Whey Protein Plus Creatine Boosts Strength." Rawson, E. Journal of Strength Cond Res, February 2004; vol 18: pp 162-167. Kreider, R. Molecular Cell Biochemistry, February 2003; vol. 244: pp 89-94. WebMD Medical News: "Supplement May Be Linked to Prostate Growth." WebMD Medical News: "DHEA May Fight Heart Disease, but How?" WebMD Medical News: "Hormone DHEA Helps Some Women Feel Better, Enjoy Sex." WebMD Medical News:"DHEA Supplement Linked to Heart Disease." WebMD Medical News: "Ginseng a No-No for Patients on Coumadin." WebMD Medical News: "Ginseng May Enhance Immune Function." WebMD Medical News: "Ginseng May Help Treat Diabetes." WebMD Medical News: "Natural Sex Boosters Gaining Ground." WebMD Medical Reference in collaboration with The Cleveland Clinic: "St. John's Wort for Treating Depression." WebMD Medical News: "St. John's Wort Helps Beat the Blues." WebMD Medical News: "St. John's Wort Depletes Cancer-Fighting Drug." WebMD Medical News: "St. John's Wort Affects Other Drugs." WebMD Medical News: "St. John's Wort Reduces Chemotherapy Effects." WebMD Medical News: "St. John's Wort Interferes With Lifesaving Drugs."

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