If recent research were a political election, vitamin D would win by a landslide. Over the past five years, more than 10,000 medical journal articles have been published on the vitamin. And the pace of research is accelerating. In just the past year, 3,500 reports have been published on vitamin D, about half focusing on people.
Three of every four Americans are either deficient or have borderline deficiencies of vitamin D. Such widespread deficiencies of the “sunshine vitamin” are truly ironic because doctors thought they were vanquished 80 years ago. So the odds are that you need to take it.
Vitamin D is actually a prehormone that the body produces when the skin is exposed to sunlight. It eventually gets converted to calcitriol, a steroid hormone. But when people don’t spend at least 15 minutes in the summer sun, they can’t make much vitamin D. Many experts, such as Michael Holick, MD, of the Boston University School of Medicine, believe that everyone, including babies and children, should take vitamin D supplements.
Here’s a rundown of the latest research.
Vitamin D Blood Levels and Longevity
In an analyses of 32 published studies involving almost 160,000 people, Danish researchers found that a combination of vitamin D and calcium supplements reduced the risk of death by 7 percent. While that finding was modest, other research shows stronger benefits.
Ellen Smit, PhD, of Oregon State University, and her colleagues analyzed 12 years of data from 4,731 people. Vitamin D blood levels were lowest in people who were physically frail—that is, abnormally thin, inactive, walking slowly, or weak. Furthermore, people with low levels of vitamin D were 30 percent more likely to die, compared with those who had higher levels of the vitamin. Smit found that people who were both frail and had low vitamin D levels were three times more likely to die compared with the healthiest subjects.
Meanwhile, Israeli researchers reported that seriously ill patients are more likely to survive if they have higher blood levels of vitamin D. In this study, Howard Amital, MD, and his colleagues tracked patients who were hospitalized for life-threatening infections, heart attacks, heart failure, and accidents. The vast majority of the 130 patients had vitamin D deficiencies. People with higher vitamin D levels lived longer.
Vitamin D and Reduced Risk of Osteoporosis
You need vitamin D to maintain healthy bones and to reduce the risk of osteoporosis. But you also need the vitamin to make muscle, which keeps those bones in place. The latest findings show that vitamin D can protect against disability, age-related frailty, and death.
Researchers at the Wake Forest School of Medicine, North Carolina, analyzed vitamin D levels in 2,099 people and tracked them for a total of six years. At the beginning of the study, two-thirds of the subjects—elderly men and women—were either marginally deficient or had clearcut deficiencies of vitamin D. People with low vitamin D levels had about a 30 percent greater risk of having some physical limitations and almost twice the risk of disability, compared with people who had higher vitamin D levels.
Meanwhile, Heike A. Bischoff-Ferrari, MD, DrPH, of the University of Zurich, Switzerland, analyzed data from 11 studies in which seniors were given either vitamin D supplements or placebos. More than 31,000 people, age 65 and older, were included in the analysis. Bischoff-Ferrari reported that vitamin D reduced the risk of hip fracture by 30 percent—but only among people who took 800 to 2,000 IU of the vitamin daily. In addition, people taking this range of vitamin D dosage had a 14 percent lower risk of other types of fractures, except for those of the backbone.
Vitamin D Levels Help with Blood Sugar Balance
Several studies have found that vitamin D supplements (often combined with calcium) can help people maintain normal blood sugar levels.
Researchers at Drexel University, Philadelphia, Pennsylvania, focused on the relationship between obesity, insulin resistance, and vitamin D levels in a study of 12,900 people.
People who were obese and had normal vitamin D levels were almost 20 times more likely to have prediabetes. But among people who were obese and had low vitamin D levels, prediabetes was 32 times more common than average. The researchers noted that obese subjects are at high risk of vitamin D deficiency because the vitamin gets stored in fat tissue, preventing it from being used by the rest of the body.
Vitamin D and Breast Cancer
Maintaining normal to high levels of vitamin D may give women an edge if they’re diagnosed with breast cancer.
Hans Wildiers, MD, of University Hospitals, Leuven, Belgium, 1,800 women whose vitamin D levels were measured at the time of diagnosis. Low vitamin D levels correlated strongly with larger tumor sizes at the time of diagnosis, whereas higher vitamin D levels were associated with smaller tumor sizes.
Furthermore, breast cancer patients with higher vitamin D levels lived longer. After three years of follow up, postmenopausal women who had high vitamin D levels were more likely to be free of cancer.
Vitamin D Helps Control Prostate Cancer
Vitamin D might not prevent prostate cancer, but recent studies suggest that the vitamin can help control the disease in its early stages and reduce the risk of dying from it.
Doctors at the Medical University of South Carolina, Charleston, reported that vitamin D supplements might reverse the growth of early prostate cancer, at least in some men. They studied men with low-grade prostate cancer who took 4,000 IU of vitamin D daily for one year.
When the men underwent follow-up biopsies, more than half of the men benefited from a decrease in their Gleason scores, a way of measuring the aggressiveness of prostate cancer. Five men showed no change, and 15 had an increase in either positive biopsy samples or their Gleason scores. Because vitamin D is so safe, it’s worth taking if you and your doctor agree to “watchful waiting.”
Meanwhile, a study in the Journal of the National Cancer Institute found that high levels of vitamin D reduces the risk of death from prostate cancer by more than half.
Vitamin D Deficiency and Multiple Sclerosis
Many researchers have noted that multiple sclerosis (MS) and vitamin D deficiency often go hand in hand. Doctors at René Descartes University, Paris, asked 156 patients with relapsing-remitting MS to take 3,000 IU of vitamin D daily. They then compared the patients’ relapse rates for a couple of years before starting vitamin D supplements and for a couple of years after taking the supplements.
The changes were dramatic. For every 4 ng/mL increase in vitamin D blood levels, the relapse rate decreased by almost 14 percent. The benefits increased until blood levels of the vitamin climbed to 44 ng/mL. That’s the amount of vitamin D needed to activate a variety of enzymes that depend on the vitamin.
How much vitamin D should you take?
Unless you’re spending a lot of time outdoors, and much of your skin is exposed without sunscreen, you’ll likely need to take vitamin D supplements. A simple blood test can determine whether or not you are deficient. The recommended dietary allowance (RDA) is 600 IU daily for ages 1-70, and 800 IU daily for ages 70 and over. However, these recommendations are considered too conservative by most experts. John Cannell, MD, director of the nonprofit Vitamin D Council recommends that adults take as much as 5,000 IU daily; infants up to 1,000 IU daily; and children and teenagers, 2,000 IU daily.
Note that vitamin D3 is absorbed by the body far better compared with vitamin D2. And if you’re obese, you’ll need more vitamin D because it gets stored in fat tissue, preventing the rest of the body from using it.
Beyond Vitamin D:
OTHER ESSENTIALS TO TAKE WITH YOUR MULTI
Adequate dosages of vitamin D are difficult to find in most multivitamin/mineral supplements, so it’s wise to take a separate vitamin D supplement along with your multi. Other smart essentials to add:
Omega-3s: Whether from fish oil or a vegetarian source such as flaxseed oil, essential omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are known to promote healthy blood pressure, triglycerides, reduce inflammation, enhance mood, and protect brain health. A typical dosage is 1,000 mg of combined EPA and DHA per day.
Probiotics: These good bacteria improve digestion and boost immune function. Take at least between 1 to 10 billion colony-forming units (CFUs) daily.
Enzymes: They’re naturally present in raw foods, and help us break down and absorb nutrients. The problem is most of us don’t get enough enzymes through our diets. For optimal digestion and nutrient absorption, take a plant-based digestive enzyme no more than 10 minutes before each meal, or with the first bite.
Calcium and Magnesium: These two minerals promote strong muscles and bones and are best taken together, as they work synergistically. Look for calcium citrate for best absorption, and aim for 1,000–1,200 mg daily, in two divided doses, with meals. Because magnesium can act as a laxative, start with 250 mg daily and work up to 1,000 mg. Calcium–magnesium formulas are also available; follow label instructions.
Lutein and Zeaxanthin: These nutrients can help protect eye health, guarding against age-related macular degeneration, cataracts, and glaucoma, The recommended dosage of lutein is 6–20 mg daily. 3 mg daily of zeaxanthin is recommended for eye health protection. Therapeutically, up to 20 mg daily of zeaxanthin is recommended.
Vitamin D Supplements
NORDIC NATURALS Vitamin D3 features cholecalciferol, the most easily absorbed and bioavailable D3, in a carrier oil of organic, extra virgin olive oil.
MEGAFOOD Vitamin D3 is made from raw, organic whole-food ingredients to deliver vitamin D in a natural form that is easily recognized and utilized by the body.
COROMEGA Omega-3+D Squeeze combines vitamin D3 and omega-3s in great-tasting (Tropical Orange) flavor, convenient individual-serving packets.
THE VITAMIN SHOPPE Vitamin D3 Chocolate Chews are a tasty way to take your D3 plus bone-strengthening vitamin K—and they’re made with natural sugars and real cocoa.
NATURAL FACTORS Vitamin D3 for Kids chewable tablets are naturally sweetened with sugar-free xylitol so they don’t promote cavities.
Jack Challem, aka The Nutrition Reporter, is the bestselling author of more than 20 books on health and nutrition, including The Food-Mood Solution and Feed Your Genes Right.