Vitamin D plays a significant role in several health conditions. It might be one of the simplest solutions to a wide range of problems. Despite the name, vitamin D belongs to a group of steroid molecules that are metabolized by the body in the liver and kidneys.1
According to the Vitamin D Council, your body undergoes numerous turns this molecule into a hormone that undergoes numerous changes during that process before it’s actually put to work managing calcium in your blood, bones and gut, and in helping your body’s cells communicate with each other.2
Vitamin D is optimally obtained through sun exposure, a small amount of food sources and supplementation. Since many dermatologists,3,4 other doctors and health care agencies like the CDC5 began telling people to avoid the sun and to use liberal amounts of sunscreen before going outside, deficiency in vitamin D has reached epidemic proportions.6,7,8,9,10
While the justification for avoiding the sun is it may reduce your risk of skin cancer, vitamin D deficiency raises your risk for many other cancers,11,12,13 including skin cancer.14
We now understand more about vitamin D than ever before in history. Many people are realizing that several of the long-held recommendations on sun exposure and vitamin D are not accurate and have contributed to declining health.
One condition recently linked to low levels of vitamin D is high blood pressure in children. In a study published in the American Heart Association journal Hypertension, researchers found that deficiency in infancy may lead to high blood pressure in later childhood and teen years.15
Childhood vitamin D deficiency predicts high blood pressure
A study from the Centers for Disease Control and Prevention16 showed 4% of those between 12 and 19 years had high blood pressure and another 10% had elevated blood pressure. An analysis of more than 12,000 participants led to these results using the 2017 clinical practice guidelines for high blood pressure.
Application of the new guidelines resulted in a net increase in the number of children and teens between 12 and 19 years with high blood pressure.17 High blood pressure may damage your heart and your health in many ways, including increasing your risk of heart failure and heart attack, stroke and kidney disease.18
Past research has demonstrated that low vitamin D levels in adults increases the risk of high blood pressure,19 but the degree to which it may affect children was unknown until a new study conducted at Boston Medical Center was published.20
In this study, researchers followed 775 children in ages ranging from birth to age 18 from 2005 to 2012 to investigate the effect vitamin D had on the development of high systolic blood pressure. For the purposes of the study,21 low vitamin D status was defined as less than 11 nanograms per milliliter (ng/mL) at birth and less than 25 ng/mL during early childhood.
The researchers22 compared those with low levels of vitamin D to children who were born with adequate levels. They found that children with low levels had about a 60% higher risk of elevated systolic blood pressure from ages 6 to 18.
Children who experienced persistently low levels throughout childhood were at double the risk of elevated systolic blood pressure between ages 3 and 18.23 Lead author Guoying Wang, Ph.D.,24 an assistant scientist at Johns Hopkins University, commented on the implications:25
“Currently, there are no recommendations from the American Academy of Pediatrics to screen all pregnant women and young children for vitamin D levels. Our findings raise the possibility that screening and treatment of vitamin D deficiency with supplementation during pregnancy and early childhood might be an effective approach to reduce high blood pressure later in life.”
Vitamin D and estrogen may reduce metabolic syndrome
Metabolic syndrome is a cluster of physiological symptoms associated with the development of cardiovascular disease and Type 2 diabetes. And, according to the Mayo Clinic, these symptoms include high blood pressure, high blood sugar, excess body fat around the waist and abnormal cholesterol or triglyceride levels.26
While having just one of these symptoms does not mean you have metabolic syndrome, it might mean you have a greater risk of serious disease. Metabolic syndrome also goes by the terms dysmetabolic syndrome, insulin resistance syndrome, obesity syndrome and Syndrome X.27
The prevalence of metabolic syndrome increases as women reach menopause, which may somewhat explain accelerated levels of heart disease after menopause.28 Scientists have theorized that these changes may be related to ovarian failure or the redistribution of fat to the stomach area, which is associated with estrogen deficiency.29
The combination of adequate vitamin D levels and normal estrogen levels have been well-documented as improving bone health.30 In a recent study,31 researchers found data to suggest that the same combination may help prevent metabolic syndrome.
They wrote that metabolic syndrome affects 30% to 60% of postmenopausal women globally. This has led some to recommend estradiol treatments for the first six years after menopause, to help prevent heart disease.
In that study,32 researchers looked at a cross-section of 616 postmenopausal women who were 49 to 86 years old and not taking estrogen, vitamin D or calcium supplements. At the end of the data collection period, they took blood samples to measure estrogen and vitamin D levels.
They found that higher levels of vitamin D were positively correlated with healthier blood pressure measurements, glucose levels and lipid profiles. The data also revealed that low estrogen levels increased the risk of metabolic syndrome in those who also had low vitamin D. They believe the results suggest33 a synergistic role between vitamin D and estrogen deficiencies in postmenopausal metabolic syndrome.
Vitamin D insufficiency may affect more than 75%
A simple math error accounts for one reason there are inaccuracies in the amount of vitamin D that is believed to be necessary to maintain good health. As pointed out in a 2014 paper,34 the then Institute of Medicine (which underwent a name change to the National Academy of Medicine in 2015)35 underestimated the need by a factor of 10 due to a miscalculation.
If corrected, the official recommendation would become 6,000 IUs a day for adults, not 600; however, the Vitamin D Council recommends 5,000.36 According to data published in the Archives of Internal Medicine,37 75% of American adults and teens are deficient in vitamin D, based on a sufficiency level of 30 ng/mL.
Insufficiency affects an estimated 1 billion people worldwide38 and may be attributed to lifestyle activities, such as a reduced number of hours spent outside in the sun. Environmental factors are also at play, relating to air pollution reducing our exposure to sunlight. A low vitamin D level is an independent risk factor for various chronic diseases.
The only way to definitively identify a vitamin D deficiency is through blood testing. However, some general signs and symptoms may tell you it’s time to be proactive. You'll find a discussion in my past article, “Top 5 Signs of Vitamin D Deficiency.”
Risk factors for low vitamin D levels include rarely spending time outdoors or always wearing sunscreen when you are, having dark skin pigmentation, being older than 50, being obese and having gastrointestinal problems. While regular, sensible sun exposure is the best way to optimize your vitamin D status, those in northern climates may need an oral supplement, especially during the winter months.
The only way to gauge how much supplement you need is to have your levels tested, ideally twice a year. Test once in the early spring, after the winter months to ensure you took enough supplement throughout the winter, and again in the early fall when your level is at its peak. You are aiming for a level between 60 and 80 ng/mL, with 40 ng/mL being the lowest cutoff for sufficiency.39,40 In fact, new research in 2018 showed that the optimal levels for cancer prevention are between 60 and 80.
Deficiency increases the risk of cancer and mortality
Although some may struggle with the concept that just one vitamin may have a significant impact on your health, wellness and longevity,41 or that vitamin D deficiency is problematic,42 there is ample research with evidence to the contrary. As I mentioned earlier, low levels of vitamin D have been associated with an increased risk for some cancers,43,44,45 bowel conditions,46,47 and skin conditions48 It also has a negative impact on your immune system.49
Vitamin D insufficiency is strongly associated with increased mortality. An epigenetic mortality risk score, developed based on whole blood DNA methylation, was used in one study50 aimed at determining whether vitamin D status was associated with this risk.
Another aim of the study was also to see if vitamin D and the mortality risk score could be used together to predict all-cause mortality in a general population of older adults. The researchers measured 1,467 participants whose ages ranged from 50 to 75. They found the combination was in fact a good indicator of the likelihood of all-cause mortality.51
Although a number of anticancer properties for vitamin D have been proposed, data suggest the metabolism and function of vitamin D is dysregulated in many types of cancers. Researchers believe this contributes to the development and progression of cancer. This means that understanding this dysregulation and function of vitamin D in cancer is of great importance.52
In addition to affecting cancers and all-cause mortality, low levels of vitamin D may also trigger dry eye syndrome53 and macular degeneration.54 I also believe vitamin D can have a beneficial impact on all autoimmune diseases. Many studies55,56,57 have found a strong link between multiple sclerosis and vitamin D deficiency.
Vitamin D plays a role in inflammatory rheumatic diseases,58 such as rheumatoid arthritis. According to one study,59 many with systemic lupus erythematosus (SLE) have presented with some level of vitamin D deficiency, defined in the study as a level of 10 ng/mL or less, or insufficiency defined between 10 and 30 ng/mL.
As reported in another study, an elderly person who has a low vitamin D level may have “a substantially increased risk of all-cause dementia and Alzheimer's.”60 Some scientists have also found links between depression and vitamin D deficiency61 and the impact low levels have on insulin resistance leading to Type 2 diabetes.62
D3 and K2 protect your arteries from calcification
While vitamin D is essential for good health and is best obtained from sensible sun exposure, if your levels are not high enough, you may need a supplement. However, it's vital you take vitamin D with sufficient amounts of vitamin K2 (MK7) as both are required to slow the progression of arterial calcification.63
Vitamin D improves bone development by helping you absorb calcium, while vitamin K2 directs the calcium to the skeleton and prevents it from being deposited in the arteries. There are two forms of vitamin K: K1 and K2. Vitamin K164 is primarily involved in blood coagulation while K2 has a more diverse range of functions.65
In one long-term study66 of 36,629 participants, researchers found vitamin K2 reduced the risk of peripheral artery disease in those with high blood pressure, but K1 had no effect. Other67 data suggest that the body absorbs vitamin K 10 times more when it is in the form of MK-7.
Vitamin K2 in the MK-7 form has been found to be bioactive. It regulates atherosclerosis, cancer, inflammatory diseases and osteoporosis.68 Vitamin K2 may lower the risk of damage to the cardiovascular system by activating a protein that prevents calcium from depositing in the walls of your blood vessels.69
If you consider supplementation, it is important to know that vitamin D2 and D3 are not interchangeable. In one study of 335 South Asian and white European women,70,71 researchers found that those taking vitamin D3 experienced twice the effectiveness in raising vitamin D levels in the body as compared to vitamin D2.
According to another data collection72 and analysis of 50 randomized controlled studies in the Cochrane database, researchers found vitamin D3 decreased mortality in elderly women who were in institutions and dependent care. Vitamin D2 did not have any solid effects on mortality.
Astaxanthin: Your internal sunscreen
Maintaining optimal levels of vitamin D through sensible sun exposure is the best way. However, too much sun may be just as much of a problem as too little. You may also want to avoid certain commercial sunscreens because they contain harmful chemicals that are easily absorbed through the skin. When this happens, you are exposed to a range of risks that outweigh the benefits.73,74
One option to consider is the use of astaxanthin, commonly called the “King of the Carotenoids.”75 The carotenoid found in astaxanthin is naturally occurring in a specific type of microalgae and in certain seafoods. The seafood with the highest amount of astaxanthin consume the microalgae, including wild-caught Alaskan salmon and krill.76
One of the benefits of this nutrient is its ability to protect your skin from the sun and to reduce the signs of aging. In one clinical trial77 involving 21 individuals, researchers found that after taking 4 mg of astaxanthin each day for just two weeks, the participants had an average 20% increase in the amount of time needed for UV radiation to redden their skin.
One study78 set out to evaluate the effects of supplementation with astaxanthin on UV-induced skin deterioration. Using 23 healthy Japanese participants in a 10-week, double-blind, placebo-controlled investigation, the researchers found those taking astaxanthin had a reduction in loss of moisture. They also had improved skin texture and appeared to experience protective effects against UV skin deterioration.
In another study79 evaluating the effects of radiation on hairless mice, researchers found dietary supplementation with astaxanthin significantly lowered wrinkle formation and water loss. They suggested that the results point to dietary supplementation with astaxanthin as being helpful for protecting the skin and slowing skin aging.
Optimize your vitamin D levels
Remember, it’s best to optimize your vitamin D levels with sunshine rather than oral supplements. Before considering supplementation with vitamins D3 and K2 MK-7 form, first get tested since you can’t know your levels by looking in the mirror. GrassrootsHealth offers a simple combined test for vitamin D and omega-3, which are both important for maintaining optimal health.
While many labs and physicians use 40 ng/mL as a cutoff for vitamin D deficiency, please remember that an ideal level for health and disease prevention is between 60 and 80 ng/mL.80 Once you know your level consider using a simple tool from GrassrootsHealth to estimate the additional amount you need to take to reach your targeted level.