I'm never quite sure what to do about vitamin supplements. Should I take them? Or should I leave them?

Sometimes I think supplements could surely help me with whatever I'm lacking in my diet. Other times I don't want to mess with what might be working just fine in my body. Now if a doctor tells me my iron is low, I'll take a supplement to boost my levels. But if there is nothing apparently off kilter in my system, I tend to just leave things alone.

I'm glad at the moment for my current plan. Because nutritionists now suspect that high doses of vitamins and minerals -- believed by some to prevent cancer -- might actually be harmful.

Think about this:

The American Medical Association journal JAMA recently reported that high doses of antioxidant supplements can be harmful. Vitamin advocates challenged the analysis, saying it excluded large studies from China and Italy showing antioxidant supplements lowered mortality risk.

Consumers still should read labels carefully.

"Some of the things called daily vitamins can be higher than what we think is desirable," says one researcher who urges consumers to look for something about 100 percent of the daily value. That's really all people need, she declares. But a healthy diet is still most important and can prevent the need for supplements altogether. Yet for those who are sick, don't have access to nutritious food or for some other reason cannot eat well, the 100-percent rule is a good guide.

In an analysis of animal research used to understand and treat human diseases, the London School of Hygiene and Tropical Medicine researchers found that using animals, such as mice, had limited value. Only half of the research done using animals translated into the same outcome for humans.

In a BBC News report over the controversy that rages regarding the wisdom of using animals in research, Professor Ian Roberts is quoted as saying, "The debate over this issue is really quite hysterical. At the moment, there is too much emotion and not much science. Anti-vivisectionists say animal testing is of no use at all, and those who do them say we would have no safe and effective treatments if we didn't." Lead researcher Roberts believes animal studies should be used, but not in all cases of research.

The value of animal research was catapulted to front page news headlines earlier this year when six men experienced tragic life-threatening side-effects as they participated in a human clinical trial of the drug TGN1412, which had previously been shown safe and effective during animal studies.

Last March, six healthy young men volunteered at Northwick Park Hospital in London as participants in a clinical trial for a drug called TGN1412, designed to treat leukemia, autoimmune and inflammatory diseases. According to the men, they were told by doctors there would be no serious short-term or long-term side effects. They were each paid £2,000. Within hours, the worst that could happen did, and the men were plunged into a nightmare beyond anything they could have imagined.

The headaches began, followed by convulsions, bloating, organ failure and comas. The men came to be known as the Elephant Men because of the swollen faces and chests they suffered. One of the men suffered gangrene -- all his toes and three of his fingers were amputated. He also suffered heart failure, kidney failure, pneumonia, septicaemia and liver failure. Recently, another participant was told he might be developing cancer as a result of the drug trial. All have been told to expect early death.

Do you feel that animal research used to test drugs and medical procedures meant to treat human ailments and diseases, are credible enough to continue, or do you believe that research using animals should be abandoned?