#102 Why Vitamin D Deficiency Accelerates Brain Aging

Doctor Rhonda Patrick here. A new study found that vitamin d supplementation was associated with a forty percent lower risk of dementia over a decade. After just five years, eighty four percent of the vitamin d supplement users were dementia free compared to sixty eight percent of the nonusers. This was a study of over 12,000 people. And vitamin d reduced dementia risk by around thirty three percent in adults with mild cognitive impairment and also had APOE four. This is a key genetic risk factor for neurodegenerative diseases. Up to twenty five percent of the population has one of these alleles, and it can double the risk of Alzheimer's disease if you have one of them. If you have two of these alleles, you can have up to a 10 fold higher risk of Alzheimer's disease. Vitamin d is not just a vitamin. Vitamin d gets converted into a steroid hormone that regulates over a thousand genes in our body. It enters the nucleus of our cells and it regulates, it activates and turns on or it suppresses and turns off up to nearly 5% of the protein encoding human genome. This is very relevant because up to seventy percent of Americans fall into a range known as deficient or insufficient. So almost thirty percent of Americans actually are vitamin d deficient. They have levels of twenty five hydroxyvitamin d below twenty nanograms per milliliter. The other forty percent or so has levels that's known as insufficient. So these are people that have vitamin d levels above twenty nanograms per milliliter, but they're below thirty nanograms per milliliter. And there's really a simple solution to avoiding this deficiency and insufficiency, and that is a vitamin d supplement. Usually, people that are vitamin d deficient, if they take around two to four thousand IUs per day, they can get to a sufficient level. There's a lot of reasons why vitamin d deficiency and insufficiency is so widespread. That is because we actually make vitamin d in our skin upon exposure from UV radiation from the sun. So anything that blocks out UVB radiation is also gonna block out the ability to produce vitamin d three in our skin. That includes sunscreen. It also includes skin pigmentation. So melanin, this is this is the darker pigmentation that serves as a natural sunscreen. That also blunts the body's ability to make vitamin d three from UVB radiation. Age. As you get older, your body is less efficient and effective at producing vitamin d three from sun exposure. In fact, a 70 year old makes four times less vitamin d from the sun than a 20 year old where you live. So living in a northern latitude, many months of the year, actually, there's no UVB radiation even reaching the atmosphere. So people that are living in more northern latitude areas are not able to make vitamin d three in their skin from the sun for many, many months out of the year. …