A 7-year follow-up study from France published in the Journal of Gerontology: Medical Science this April showed that a higher vitamin D intake was associated with a lower risk of Alzheimer’s disease.
The study that followed a group of elderly women ( average age 79.8 years) for 7 years found that those who consumed the least amounts of vitamin D were at higher risk of developing Alzheimer’s disease.
The researchers explained two possible mechanisms of action:
- In previous studies, vitamin D has been linked to hippocampus protection in rodents. The hippocampus is the part of the brain responsible for consolidation of short-term memory into long-term memory and spatial navigation. It is one of the first areas of the brain to be affected during Alzheimer’s disease.
- Vitamin D may play a role in influencing the production and clearance of beta-amyloid proteins in the brain. Beta-amyloid deposits have been associated with increased brain cell damage, cognitive decline and increased risk of Alzheimer’s disease.
The researchers also pointed out that the potential benefits may be due to the nutritional content of vitamin D-rich foods namely fish which are rich in omega-3.
We all know that Vitamin D is the sunshine vitamin, but where can it be found in foods and how can we ensure we are getting enough?
The body needs 5 micrograms or 200 International Units (IU) of vitamin D per day.
- Twenty minutes of daily exposure to the sun are enough for the body to manufacture vitamin D. However, during winter months and whenever the sunshine is weak, the body is not making enough of the vitamin and we have to resort to foods and supplementation. Start wearing sunscreen for any time spent beyond the twenty minutes.
- Fish, egg yolks and dried shiitake mushrooms are the only foods that naturally contain vitamin D.
- Good sources of vitamin D are fortified foods and beverages such as milk, fortified soy, rice and nut beverages and margarine. Below is a table with natural and fortified sources and the percentage daily value (%DV) of vitamin D. 5mcg= 200IU= 100%DV
| Natural Sources | %DV |
| Herring, 3 oz | 277 |
| Salmon, canned, 3 oz | 106 |
| Halibut, 3 oz | 102 |
| Cod liver oil, 1 tsp | 90 |
| Catfish, 3 oz | 85 |
| Oyster, 3 oz | 61 |
| Dried Shiitake mushrooms, 4 | 50 |
| Sardines, canned in oil, 1/2 cup | 41 |
| Tuna, canned in oil, 3 oz | 40 |
| Shrimp, 3 oz | 26 |
| Egg, cooked | 5 |
| Fortified Sources (check the labels/ DV on label is stated per serving) | |
| Fortified Tofu, 1/5 block | 24 |
| Cow’s milk, 8 oz | 20 |
| Fortified rice milk, 8 oz | 20 |
| Fortified soy milk, 8 oz | 20 |
| Fortified orange juice, 8 oz | 20 |
| Fortified cereal, 3/4 cup | 8 |
- As with any kind of supplementation, it is better to get a blood test to determine your body’s levels and check with your doctor for a prescription. Most adult multivitamins contain 400IU of vitamin D. The amount varies between brands in the supplements that contain vitamin D alone or calcium and vitamin D.
For a list of other foods that can help improve your memory, you can check an earlier post on the subject.
For a summary of the study, you can check Nutra Ingredients -USA.
Spring is here! Time to reap the benefits of the great outdoors; mountain hikes, seaside walks, beautiful sunshine and fresh air!
