The past few weeks have brought disheartening news about dietary supplements.

In early October a study in the Journal of the American Medical Association (JAMA) showed that omega-3 fatty acids and antioxidant supplements provided no benefit to patients who’d suffered acute lung injuries and in fact may have caused them harm; that study was stopped early because the lack of benefit and potential for harm became quickly apparent.

Early this week the Archives of Internal Medicine published research reporting that use of several common dietary supplements is linked with a slightly increased risk of death among older women.

And research published Tuesday in JAMA found that Vitamin E raises men’s risk of prostate cancer.

(Another piece of research published in the journal Neurology linked memory loss to Vitamin B12 deficiency in older people but did not examine whether taking Vitamin B12 supplements would improve memory.)

As I wrote in late August, dietary supplements should be used sparingly, if at all, and mostly to ensure your body gets enough of four key nutrients -- potassium, calcium, Vitamin D and fiber -- that our diets tend to fall short on. (Some people may also need extra iron, folate or Vitamin B12.)

As Duffy MacKay, vice president for scientific and regulatory affairs for the Council for Responsible Nutrition, a dietary supplement trade group, says, supplements should be used just as their name implies -- to supplement a healthful diet and overall lifestyle.

A quick reminder about studies: Science is meant to proceed in increments, with each new finding contributing to our body of knowledge and to be assessed within the context of that body of knowledge. As MacKay pointed out to me on the phone yesterday, these days scientific studies are released to the media and shared with the general public the day they’re published, before the scientific community has a chance to cogitate over them. That accounts for the information whiplash we experience: One day, Vitamin E is a miracle nutrient, the next day a demon that might do us in.

I am no particular fan of dietary supplements. But I don’t think it’s a good idea to switch your dietary habits -- including whether you take supplements or not -- on the basis of any single study, or even three that happen to come out around the same time.

Have you altered your stance toward dietary supplements, including multivitamins, in light of recently published research?