Your body needs vitamins to stay healthy. But, with possibly one exception, there’s not much reason to believe that taking high doses of vitamins in the form of dietary supplements will improve your memory and cognitive skills.
Some evidence for the power of vitamin B12
The Recommended Dietary Allowance (RDA) for vitamin B12 is 2.4 mcg a day. Being deficient in this vitamin becomes more common with age, and can lead to a variety of health problems, including difficulty thinking and a general loss of mental clarity. Older people may, in general, absorb less vitamin B12 because they produce less of a substance called intrinsic factor in the stomach. Also, they may end up eating fewer foods that contain B12.
Researchers say that while it’s too soon to recommend taking B12 to protect your memory, it can’t hurt to eat foods rich in this vitamin, such as fish and poultry. And taking a dietary supplement can help if there’s any risk for a B12 deficiency, so ask your doctor if you suspect this may be the case for you. Thankfully, a simple blood test can identify such a deficiency.
Vitamin B12 and certain other B vitamins—especially B6 and folate (folic acid)—may also play a role in cognitive health by lowering homocysteine, an amino acid linked to heart attacks, strokes, and Alzheimer’s disease.
In a study reported in the Archives of Neurology, researchers assessed the B6, B12, and folic acid intakes of 965 people age 65 or older who showed no signs of dementia. They found that the risk of developing Alzheimer’s down the road was 50 percent lower among people with the highest folic acid intake. In this study, vitamin B6 and B12 levels had no apparent tie to Alzheimer’s disease risk. Still, this association could not prove that these vitamins lowered the risk for Alzheimer’s or that people who did not have Alzheimer’s had a diet richer in these vitamins.
The bottom line: It’s still unclear whether supplementation with vitamin B12, B6, or folic acid can reduce the risk of dementia.
Thiamin (vitamin B1)
A thiamin deficiency can lead to numerous health problems, such as memory deficits, confusion, and difficulty walking. Alcoholism is a common cause of thiamin deficiency. Because people who have alcoholism often fill up on empty calories from alcohol, their diets lack many essential nutrients, one of the most important being thiamin. If caught in time, a thiamin deficiency can be treated with thiamin supplements, a proper diet, and cessation of drinking.
Laboratory research suggests that vitamin D plays a role in protecting neurons, supporting brain function, and reducing inflammation. And observational studies have found links between low blood levels of vitamin D (25-hydroxyvitamin D) and dementia. In one study, researchers examined cognitive assessments and blood samples from more than 3,000 older adults and found that those with a vitamin D deficiency had a four times higher risk of cognitive impairment when compared with those with adequate levels.
In another study, researchers interviewed, examined, and tested more than 800 adults every three years over an eight-year period. Those who were severely deficient in vitamin D experienced greater declines in scores on cognitive tests compared with those who had normal levels.
Vitamin D deficiency is common in people over age 60, particularly those who spend little time outdoors. (The body needs sunlight to manufacture vitamin D in the skin.) If you’re older and concerned about having low levels of vitamin D, it makes sense to ask your doctor about getting your levels tested; a deficiency can be corrected with vitamin D supplements. For those who don’t have a deficiency, more study is needed to determine whether these supplements can make any difference when it comes to staying sharp and staving off dementia.
Antioxidant vitamins have been studied for their potential to protect against Alzheimer’s disease. Antioxidants are substances that neutralize free radicals (molecules created as the body uses oxygen). Free radicals can damage DNA within cells and are associated with several aging-related diseases, including heart disease.
But the evidence for taking vitamin C and E supplements to protect against dementia is mixed. While several large, long-term observational studies suggest they may help, others showed no protective effects.
A large study published in JAMA Neurology in May 2017 found no dementia-protective effect for vitamin E and selenium in about 3,800 men. The participants in this study, who were all at least 60 years old, were divided into four groups. Each group took supplements or a placebo for up to 15 years as follows: vitamin E (400 IU per day), selenium (200 mcg per day), vitamin E plus selenium, or placebo. All participants were evaluated periodically for dementia using screening tests and medical records. Analysis showed that about the same percentage of each of the four groups (4 percent) developed dementia.
In terms of vitamin E alone, most clinical research hasn’t found evidence that supplements can help delay or prevent dementia, or even preserve memory in any manner. If you decide to take vitamin E supplements anyway, be sure to talk to your doctor first, since high levels have been linked to bleeding and increased risk for prostate cancer and other health problems.
The bottom line
Instead of spending money on vitamin supplements to prevent Alzheimer’s disease, a better investment would be to exercise regularly and follow a healthful diet to lower your risk for heart disease; there’s convincing evidence that this can also help reduce the risk for age-related cognitive decline.