The hardest vitamin to obtain through diet could be one of the most important ones for brain health. You already know vitamin D as a key building block for bones—but it also has a starring role in maintaining normal brain functions and protecting brain cells from damage, a role that grows as the brain ages.

With age, brain cells become more susceptible to damage from calcium-induced stress. Vitamin D may help prevent calcium from entering brain cells by blocking off key channels. It may also prevent brain- cell loss and increase the ability of nerve cells to communicate with one another, possibly by increasing activity of the neurotransmitter acetylcholine.

Vitamin D helps regulate the brain’s immune system and inhibit the inflammatory mediators (cytokines) involved with immunity and inflammation. So when levels of vitamin D are low, the body has less ability to fight inflammation in the brain, inflammation that typically increases with age. This is important because inflammation that destroys brain cells may contribute to the cognitive decline seen in conditions such as Alzheimer’s disease and Parkinson’s disease. Low levels of vitamin D have also been linked to other forms of dementia, memory loss and depression. A research review in Touch Neurology pointed out that 70% to 90% of older adults with cognitive problems are deficient in the vitamin.

MAKING UP THE “D”-IFFERENCE

The National Institutes of Health suggests that people age 50 to 70 get 600 IU of D a day, 800 IU per day for people age 71 or older. It’s a challenge to get vitamin D naturally, especially as we age. Vitamin D is made by the skin, but only when the skin is exposed to enough sunlight. Seniors face two problems here. Many people spend more time indoors as they age. And even when you get enough sunlight, “older” skin—skin that has become thinner and more fragile—isn’t as efficient at making vitamin D as it used to be. At age 70, your skin makes 50% less vitamin D than it did at age 20.

It also becomes progressively harder to get vitamin D through diet because problems such as gastritis and decreased liver metabolism, common in seniors, limit the body’s ability to absorb vitamin D through the digestive system. Some people avoid dairy altogether because of lactose intolerance and/or GERD.

To treat or prevent vitamin-D deficiency, supplements are often the answer. But first it’s important to find out your exact level of D with a blood test. In fact, if you’re over age 60, you should get your vitamin-D level checked annually, or more often, if needed.

If you are low on D, talk to your doctor about a plan to get up to a brain-healthy level. Studies suggest a daily dose of 1,000 IU. (It’s possible to overdose with vitamin-D supplements, but very unlikely as you would need to take the amount associated with toxicity of 10,000 to 40,000 IU per day.) Some people might need a high dose for a short period of time and then a lower maintenance dose. Your doctor can recheck your blood levels after a few months and adjust the dose as needed. The two forms available are D-2 and D-3. Most doctors agree that D3 is more effective at raising levels of vitamin D.

For more on feeding your brain well, check out “Better Gut Health=Better Brain.”