Jury still out on beta-carotene for forgetfulness
Publication Date:12/11/2007
Taking beta-carotene supplements for many years could play a small part in helping older men delay a decline in their memory, a new study says. But beta-carotene can be harmful for some people, such as smokers.
What do we know already?
Some doctors think that nutrients called antioxidants, such as vitamin C, vitamin E and beta-carotene, could help protect us from the effects of ageing. It's possible that these nutrients, either in the foods we eat or as supplements, could protect against age-related memory loss or even Alzheimer's disease. However, the research on antioxidants is mixed, and studies are hard to do, as the potential benefits may only be obvious after many years.
Researchers have now published the results of a 20-year study looking at whether beta-carotene supplements could help people stay mentally sharp for longer.
What does the new study say?
The new research hints that beta-carotene could play a part in preventing forgetfulness in older men. But the possible benefits are small, and would mean taking supplements for 15 years or more.
Tell me more about the study's findings
The study began in 1982, and followed more than 20,000 American men who all worked as doctors. It originally looked at whether taking aspirin or beta-carotene could help to prevent heart problems or cancer. The men taking aspirin were less likely to have heart attacks, but there were no obvious benefits from beta-carotene.
At the end of the study, most of the men were in their late 60s or early 70s. The researchers wondered whether beta-carotene had helped prevent the memory loss that can happen as people get older. Most of the men had been taking beta-carotene for between 15 and 20 years at this point, but some had joined the study later and only taken it for about a year.
About 6,000 men had taken beta-carotene supplements. The researchers asked these men to do memory and word tests, and compared the results with men who'd taken a dummy treatment (a placebo). There was no benefit to taking beta-carotene for just a year. Men who'd taken it for more than 15 years did better on the memory and word tests, but only slightly.
It's hard to say whether the small difference in test scores amounts to an improvement you'd actually notice. The researchers think that taking beta-carotene for at least 15 years would help you end up with the mental alertness of someone a year younger than you.
Where does the study come from?
The study was done by researchers from Harvard Medical School and the Harvard School of Public Health, both in Boston, Massachusetts. It appeared in the medical journal Archives of Internal Medicine, which is published by the American Medical Association.
How reliable are the findings?
There was one big problem with the study. A few years after the first set of memory tests, two-thirds of the men were tested again. This second set of tests didn't show any benefit from beta-carotene.
It's not clear why the second set of results were different. But getting conflicting results from the study is worrying. Either the positive or negative result could have been down to chance, making it hard to say whether beta-carotene helps with memory or not.
What does this mean for me?
Based on this study, there's no strong evidence that beta-carotene supplements can prevent memory loss. And beta-carotene can be harmful for some people. Smokers who take beta-carotene have a higher risk of getting lung cancer.
The study only looked at men, so it can't tell us anything about the possible benefits or risks for women taking beta-carotene.
What should I do now?
The Food Standards Agency (FSA) is the government body that advises the public about food. It says that you should be able to get all the beta-carotene you need from a healthy, balanced diet. The FSA also warns that taking high doses of beta-carotene could be harmful.
If you do take a vitamin supplement containing beta-carotene, you shouldn't take more than 7 milligrams (mg) a day without talking to your doctor. The men in the study were taking a dose of 50 mg every two days.
People who smoke, or who might be at risk of lung cancer for another reason, shouldn't take beta-carotene at all.
From:
Grodstein F, Kang JH, Glynn RJ, et al. A randomized trial of beta carotene supplementation and cognitive function in men. Archives of Internal Medicine. 2007; 167: 2184-2190.
News Archive
© BMJ Publishing Group Limited ("BMJ Group") 2007. All rights reserved
This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
