Getting Enough Vitamin D to Avoid Dementia

by Dorian Martin Patient Advocate

A study recently found that having a deficiency in vitamin D is associated with a substantially higher risk of developing dementia, including Alzheimer’s disease, in older adults. The researchers found that study participants who were severely deficient were more than twice as likely to develop cognitive impairment. So how can you get more vitamin D?

Amount of Vitamin D

The recommended dietary allowance of vitamin D for adults is 600 IU (or 15 mcg a day) up to the age of 70. At the age of 70, the amount increases to 600 IU (or 20 mcg a day). In general, people who are over the age of 50 need higher amounts of vitamin D than younger people. It’s important to talk to your doctor about the right amount for your individual situation.


Exposure to sunlight is an effective way to get vitamin D. Ultraviolet B radiation penetrates uncovered skin and is converted into vitamin D. Some researchers recommend 5-30 minutes of sun exposure between 10 a.m.-3 p.m. at least twice weekly in order to get vitamin D. However, the season, time and length of day, cloud cover, smog, skin melanin content and sunscreen can affect vitamin D synthesis.

Food sources of vitamin D

Vitamin D is a fat soluble vitamin. It actually is not naturally available in many foods so food producers often add it to foods. For instance, most milk in the United States is fortified with 400 IU of vitamin D per quart. However, foods made from milk, such as cheese and ice cream, are usually not fortified. Some cereals, orange juice, yogurt and margarines also are fortified.


Some types of seafood have good quantities of vitamin D. The best is salmon, which contains 127 percent of the recommended daily amount in one serving. Sardines also are a good source, having 40 percent of the recommended daily value of vitamin D. Tuna also has 23 percent of the recommended daily amount of vitamin D. Mackerel also is a good source of this vitamin.


Shiitake mushrooms have 5 percent of the recommended daily value of vitamin D. In addition, some mushrooms are being exposed to ultraviolet light to boost the amount of vitamin D that they have. Therefore, check the packages when purchasing mushrooms to see if they have received this additional boost.

Cow's milk and liver

Cow’s milk has 15 percent of the recommended daily amount of vitamin D due to fortification. The George Mateljan Foundation stated that whole milk from grass-fed cows that are outdoors frequently does contain vitamin D, studies have not documented predictable levels of vitamin D in non-fortified, grass-fed whole milks. Beef liver also has small amounts of vitamin D.


One pasture-raised egg has about 10 percent of the recommended daily value of vitamin D. The vitamin D is concentrated in the yolk so you need to eat the whole egg in order to absorb it.


Because it’s difficult to get enough vitamin D from food alone, you may want to take a vitamin D supplement. Vitamin D is included in most multi-vitamins, often in strengths from 50-100 international units. Therefore, be sure to read the packaging when selecting your multi-vitamin. Cod-liver oil also is a great source since 1 tablespoon has 340 percent of the recommended daily value.

Dorian Martin
Meet Our Writer
Dorian Martin

Dorian Martin writes about various topics for HealthCentral, including Alzheimer’s disease, diet/exercise, menopause and lung cancer. Dorian is a health and caregiving advocate living in College Station, TX. She has a Ph.D. in educational human resource development. Dorian also founded I Start Wondering, which encourages people to embrace a life-long learning approach to aging. She teaches Sheng Zhen Gong, a form of Qigong. Follow Dorian on Twitter, Facebook or Instagram at @doriannmartin.