Life Extension Magazine August 2013
The Overlooked Importance of Vitamin D Receptors
By Logan Bronwell
Vitamin D Protects Brain Cells
Vitamin D is especially powerful against neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Long-term studies show that low vitamin D levels increase the risk of cognitive decline of any kind by 41 to 60%; increase the risk of Alzheimer’s dementia by 77%; and increase the risk of non-Alzheimer’s dementia by nearly 20-fold.7,42,43 And higher vitamin D concentrations are correlated with lower severity in Parkinson’s disease.44
Even though existing treatments for neurodegenerative diseases can only treat symptoms and temporarily slow their progression,45 vitamin D has been found to reverse neurodegenerative decline. A recent study showed that adding vitamin D to a standard memory drug, meantime, for 6 months in newly diagnosed Alzheimer’s patients produced significant gains in cognition, suggesting a synergism between vitamin D and the drug.46
Supplementation with vitamin D has such potent benefits for the brain because the brain relies on vitamin D receptors for protection against a variety of destructive processes.47 Vitamin D has been shown to have a critical role in nerve cell growth and differentiation, nerve transmission, and the “plasticity” of connections that’s so essential for normal learning and memory.48 Without adequate vitamin D, all of those functions suffer, and some fail.
In Alzheimer’s disease, that failure is manifested as increased amounts of the abnormal, inflammatory protein called amyloid beta (or Abeta). Studies show that when vitamin D is added to cultures of cells from Alzheimer’s patients, it speeds the clearance of Abeta.49
When laboratory animals bred to spontaneously develop Abeta plaques are supplemented with vitamin D, they show a decrease in brain inflammation, an increase in protective nerve growth factor, and they develop fewer Abeta plaques compared to control animals.50
Even normal elderly lab rats (those without Alzheimer’s) can experience cognitive benefits from vitamin D supplementation. Older rats have significant difficulty with cognitive testing, along with elevated levels of pro-inflammatory cytokines, decreased levels of anti-inflammatory cytokines, and higher levels of Abeta proteins in their brains.51 But supplementing with vitamin D for as little as 21 days significantly reversed the inflammatory changes and improved clearance of Abeta.51 This shows the potential of vitamin D to prevent the onset of age-related cognitive decline—even when it’s not associated with Alzheimer’s disease.
Vitamin D can benefit people with Parkinson’s disease as well. In humans, it’s already known that vitamin D supplementation reduces falls and improves balance in healthy older adults—two problems often faced by patients with Parkinson’s.44 A randomized, placebo-controlled clinical trial has shown that 1,200 IU/day of vitamin D3 prevents deterioration in Parkinson’s disease patients over a 12-month period.52 Intriguingly, this effect depended on the patients’ type of vitamin D receptors in brain tissue.
Vitamin D Blocks Cancer
Low levels of vitamin D in the blood are strongly associated with elevated cancer risk. Compared to people with higher vitamin D levels, those with low levels have an 83 to 150% increased risk of developing cancer.53-55
This strong correlation is due to vitamin D receptors, which regulate a number of signaling pathways involved in inflammation, tumor growth, and immune system surveillance for cancer—especially in the epithelial cells of the skin, breast, prostate, and colon (tissues that are prone to cancer development).56-58
The problem is that in cancer cells, the vitamin D receptor is dramatically decreased, leaving cells unregulated and prone to reproduce in an out-of-control fashion.57 Treating cancer cells in culture with vitamin D, however, produces a number of actions that help fight against cancer: it decreases tumor cell proliferation, quells inflammation, reduces invasiveness, and increases tumor cell death (apoptosis).57,59,60
The benefits of these actions are especially seen in cancers of the breast, prostate, and colon.
In animals with experimentally induced breast cancer, for example, these effects of vitamin D reduced the incidence, number, and size of tumors, particularly when vitamin D was combined with EPA and DHA from fish oil.59,61
In vivo studies have shown that activated vitamin D3 has some benefits specific to estrogen-dependent breast cancer. It reduces overall tumor-promoting estrogen effects by decreasing the expression of the aromatase enzyme that makes estrogen in breast tissue and by decreasing the expression of the alpha form of estrogen receptor that aggravates certain malignancies.60
Human studies are now pointing in a similar direction. In the large Women’s Health Initiative study, even a low dose of 400 IU/day of vitamin D combined with calcium was associated with an up to 20% decrease in breast cancer in women who had not taken supplements previously.62,63
Cancers of the prostate also respond to vitamin D supplementation, as shown by a study in which men with early prostate cancer received4,000 IU/day for a year.64 Fifty-five percent of supplemented subjects showed a decrease in tumor-positive biopsies or a decrease in the Gleason tumor score, while an additional 11% showed no change (meaning the cancer had not progressed). Since prostate cancer is often such a slow-growing malignancy, it is ideal for prevention with vitamin D.65
Cancers of the colon and rectum usually start as benign polyps (or adenomas), which progress to malignancy as a result of chronic inflammation. Colorectal adenoma patients who took 800 IU/day of vitamin D3 experienced a significant 77% decrease in inflammatory markers that can promote cancer development.56 In a similar group of patients, 800 IU/day of vitamin D3 produced marked decreases in levels of the tumor promoter beta-catenin, with an increase in the tumor suppressor known as APC.66
Vitamin D and Autoimmune Disease
Vitamin D is essential for maintaining a balanced immune system. Immune system cells are well-supplied with vitamin D receptors, which along with vitamin D itself, help the system modulate its response: from “attack mode” in the face of pressing threats to “cleanup and wind-down” mode once the threat is past and tissue damage becomes a concern.67-69
Vitamin D plays a role in the onset and progression of autoimmune diseases, including type I diabetes, lupus, rheumatoid arthritis, psoriasis, and multiple sclerosis.68,70-72
Fortunately, studies show that restoring vitamin D levels to the healthy range through supplementation can help patients with autoimmune diseases. Supplementation has been shown to increase the number of regulatory T-cells that restore immune system activity to its normal state, preventing the overactive response characteristic of autoimmune diseases.73
The increase in vitamin D levels through supplementation has a number of disease-specific benefits:
- It causes a decline in the disease activity in rheumatoid arthritis and lupus.71,72
- It reduces the risk of developing type I diabetes and preserves insulin-producing pancreatic cells once the disease has started. 74
- It suppresses the development of multiple sclerosis in animal models of the disease, and a large human trial has shown that supplementation was associated with a 40% reduction in the risk of developing multiple sclerosis.70,75
The Vitamin D Solution
With over 1 billion people worldwide faced with insufficient levels of vitamin D, it’s easy to see why so many of these life-threatening diseases are skyrocketing to epidemic proportions.
Fortunately, the solution is straightforward. Start by taking a high quality vitamin D3 supplement of at least 2,000 IU daily (small children need at least 400 to 1,000 IU).8,9 Next, get your vitamin D level checked as soon as possible. Be sure the lab tests for “25-hydroxyvitamin D,” which is the best measure of vitamin D status.8 To get your blood concentration up to the sufficient level, you’ll need to take 100 IU of additional D3 for each 1 ng/mL you need to raise it.8
So if your level comes in at a low 20 ng/mL, you’ll need to take an additional 3,000 IU (100 IU x 30 ng/mL) to get yourself up to 50 ng/mL. Recheck the level in 2 to 3 months. Once you are in the sufficient range, you might be able to maintain that level by taking 2,000 IU daily, though most people nowadays are taking doses of 5,000 IU and higher to get their levels closer to high optimal range of 80 ng/mL. Confirm this with repeat testing at least once a year.76 Many people, especially those with pre-existing chronic illness, find they need more to boost their levels adequately.76,77
Despite reams of evidence to the contrary, mainstream medicine continues to mainly regard vitamin D as essential only for healthy bone maintenance. But the discovery that the vitamin D receptor is found in virtually all human tissues has suggested to many that the vitamin (actually a hormone) is vital for most human functions.
Frighteningly, though, the majority of Americans have insufficient vitamin D levels to support good health, resulting in an increase in a host of chronic diseases.
Supplementing with 2,000-8,000 IU/day of vitamin D3 is the best way to get your levels back to normal and to promote your body’s maintenance—not just of bone health, but of robust cardiovascular, metabolic, neurologic, and immune function, while also preventing cancers of the breast, prostate, and colon, and likely many others.
Remember to take your vitamin D with the meal of the day that contains the most fat, as this greatly enhances vitamin D absorption.
You owe it to yourself to get your vitamin D level tested now—but don’t wait for the results. Odds are that you haven’t got enough vitamin D in your body for optimal health, so you should begin a vitamin D3 supplement today.
If you have any questions on the scientific content of this article, please call a Life Extension® Health Advisor at 1-866-864-3027.