Low Vitamin D: A Global Concern

Recent studies suggest that vitamin D is much more important in fighting off disease than previously thought. Being deficient in this vitamin puts one at risk of diseases such as cancer, osteoporosis, and multiple sclerosis. Chances are that if you live in a northerly geographic region you do not get enough vitamin D. Persons who live a rather sedentary lifestyle and do not get outside for at least a 15-minute daily walk in the sun are in the same position. Latinos, African-Americans and others with dark skin tend to have much lower levels of vitamin D, as do people who are overweight or obese. All around the world millions of persons suffer from vitamin D deficiency. This phenomenon is so common that it affects persons on every continent, of all ethnic groups, and across all ages. Some surveys suggest that perhaps half of the world’s population has inadequate blood levels of vitamin D. Sadly, physicians, even in industrialized countries, are seeing the resurgence of rickets, the bone-weakening disease that had been largely eradicated through vitamin D fortification.

As with most research findings, there is plenty of debate. Indeed, as opposed to what many people think, there are few certainties in science; its nature is to be open to criticism, discussion, and revision. The Institute of Medicine (IOM) released a report in November 2010 which recommends a daily vitamin D intake of 600 IU per day, for people ages 1 to 70, and 800 IU, for people over age 70—the report referred to persons living in the U.S. and Canada. The report also recognized the safety of vitamin D by increasing the upper limit from 2,000 to 4,000 IU per day, and acknowledged that even at 4,000 IU per day, there was no good evidence of harm.

Some in the scientific community believe the new guidelines are too conservative about the intake, and that they do not give due consideration to the latest findings about vitamin D and health. They contend that the new guidelines are not enough to prevent chronic disease, and they are not sufficient to help those who have problems with their bones. This is an important debate, and in order to understand it better it is necessary to know the origins of vitamin D and how it functions in the human body.

Vitamin D Sources and Function

Our body makes vitamin D and it is also a nutrient we eat. The body produces vitamin D from cholesterol, which itself is triggered by sun lighting on the skin. Yet many persons do not make enough vitamin D from the sun, persons with darker skin, those who are overweight, and persons who use products that block sunlight being among them. Correctly applied sunscreen reduces our ability to absorb vitamin D by more than 90 percent.

To be sure, not all sunlight is of the same quality and intensity: The sun’s ultraviolet B (UVB) rays—the so-called “tanning” rays, and the rays that trigger the skin to produce vitamin D—are stronger near the equator and weaker at higher latitudes. Indeed, persons who live in places prone to considerable cloudiness and rain can suffer from vitamin D deficiency. The other way we get vitamin D is to eat food that contains a lot of it. However, few foods are naturally rich in vitamin D, so the biggest dietary sources of vitamin D are fortified foods and vitamins supplements.

Vitamin D helps the body absorb and retains calcium and phosphorus, which are critical elements for building bone. Laboratory studies show that vitamin D can reduce cancer cell growth, can increase muscle strength, and can help control infections. There may yet be other functions for vitamin D, and scientists continue to explore the many other uses for this important substance.

New Vitamin D Research: Beyond Building Bones

Vitamin D research has proved to be of considerable fecundity. Although there have been many reports issued over the years, there are only a few that offer enough evidence to constitute a clear medical breakthrough. Here we provide the more promising areas of vitamin D research, highlighting the complex role of vitamin D in disease prevention—and the many unanswered questions that remain.

Vitamin D and Bone and Muscle Strength

A number of random trials have shown that high doses of vitamin D supplements help reduce bone fractures. A summary of the evidence comes from a combined analysis of 12 fracture prevention trials that included more than 40,000 elderly people, most of them women. Researchers found that high intakes of vitamin D supplements—of about 800 IU per day—reduced hip and non-spine fractures by over 20 percent, while lower intakes (400 IU or less) failed to offer any fracture prevention benefit.

It has been shown that vitamin D may also help increase muscle strength, which can help prevent elderly persons from falling, a common problem that leads to increased rates of disability and death among them. A combined meta-analysis found that taking 700 to 1,000 IU of vitamin D per day lowered the risk of falls by 19 percent; the combined studies also show that taking 200 to 600 IU per day offered no such protection. Based on this data, the International Osteoporosis Foundation recommends that adults over age 60 maintain vitamin D blood levels of 30ng/ml. This means that most people will need vitamin D supplements of at least 800 to 1,000 IU per day, and possibly higher, to reach these levels.

Vitamin D and Heart Disease

The heart, as a skeletal muscle, is a receptor of vitamin D. A number of studies have found that lack of vitamin D is linked to heart disease. The Health Professional Follow-Up Study observed the vitamin D blood levels in nearly 50,000 men who were healthy. They followed the same group for 10 years and found that men who were low in vitamin D were twice as likely to have a heart attack as men who had adequate levels of vitamin D. Other studies have linked low vitamin D levels to an increased of heart failure, sudden cardiac death, stroke, overall cardiovascular disease, and cardiovascular death. There is some evidence that vitamin D plays a vital role in controlling blood pressure and preventing artery damage. This goes some ways in explaining the findings above. However, more research is needed before a sounder conclusion can be made.

Vitamin D and Cancer

Nearly 30 years ago, researchers discovered an interesting correlation between colon cancer deaths and geographic location. They found that people who lived at higher latitudes, such as in the northern U.S. or Canada, had higher rates of death from colon cancer than people who lived closer to the equator. The sun’s UVB rays are weaker at higher latitudes, and in turn, people’s vitamin D levels in these high latitude locales tend to be lower. Researchers formed the hypothesis that vitamin D deficiency can lead to an increased risk for getting colon cancer

Some time has passed, but dozens of studies suggest a relationship does exist between low vitamin D levels and increased risks of colon and other cancers. The evidence is strongest for colorectal cancer, with observational studies have found that persons with lower vitamin D levels are at higher risk of getting such diseases. Vitamin D levels may also predict cancer survival, but there is as yet little evidence to support this. However, it is not yet certain that taking vitamin D supplements necessarily lowers the risk of contracting cancer. This latter idea will be tested in the VITAL trial. The VITAL trial will look specifically at whether vitamin D supplements lower cancer risk. However, it is likely to be years before the trial produces any results. Additionally, the VITAL trial could fail to detect a real benefit of vitamin D. There are several reasons for this. First, if people in the placebo group decide to take their own vitamin D supplements, the differences between the placebo group and the supplement group could be minimized. Second, the study may not follow participants for a long enough time to show a cancer prevention benefit; or study participants may be starting supplements too late in life to lower their cancer risk.

In any case, given the evidence now on hand, 16 scientists have circulated a “call for action” on vitamin D and cancer prevention. Given the high rates of vitamin D inadequacy in North America, the strong evidence for reduction of osteoporosis and fractures, the potential cancer-fighting benefits of vitamin D, and the low risk of vitamin D supplementation, these scientists recommend vitamin D supplementation of 2,000 IU per day. The Canadian Cancer Society has also recommended that Canadian adults consider taking vitamin D supplements of 1,000 IU per day during the fall and winter. They also recommend that people who are at high risk of having low vitamin D levels because of old age, dark skin, or geographic location take vitamin D supplements year round.

The Benefits of Boosting Calcium: All the Way to Weight Loss

An estimated 44 percent to 87 percent of Americans don’t get enough calcium, including children, who are falling severely short on this mineral critical for proper growth and development. Unfortunately, there are not usually any obvious symptoms of a calcium deficiency, and people can go for years in a calcium-deficient state before any noticeable problems occur. Most of the symptoms that might occur due to a calcium deficiency would be seen only if calcium levels are low in the blood. Because the body is very good at keeping the blood calcium levels steady (often at the expense of bone strength), most people will never experience any symptoms of a deficiency until their bones are significantly weakened and fracture.

The benefits of boosting calcium go far beyond the obvious reasons of helping to normalize calcium levels and ensure healthy physiological processing. Several recent studies have shown links between increased calcium intake and specific health benefits in any array of conditions.

Premenstrual syndrome. It is found that a 50 percent decrease in PMS symptoms for women given calcium supplementation, compared to a 30 percent decrease for the placebo group. No other drug addresses all these symptoms as effectively. Another report, based on an epidemiological study of more than two thousand women, found a strong link between calcium and vitamin D intake and the risk of PMS. A high intake of calcium and vitamin D may reduce the risk of PMS.

Weight loss. Other studies have demonstrated links between increased calcium intake and weight loss. One of the researchers reported that calcium plays a key role in metabolic disorders linked to obesity, and also that high calcium diets lead to the release of a hormone that leads to the body’s fat cells losing weight. This is the basis on which the milk industry claims its product helps cinch a waistline, bolstering the “it does a body good” mantra.

High blood pressure. Clinical trials have also linked how calcium levels with high blood pressure. Argentinean research showed that women who take calcium during pregnancy may lower their children’s future risk of blood-pressure problems. Studies done at Rockefeller University showed that calcium supplements were of general benefit to both mother and baby during pregnancy.

Colon cancer. Researchers have linked calcium with the prevention of colon cancer.

Stroke. Harvard scientists reported on a link between increased calcium and the prevention of stroke.

Cholesterol. Researchers have shown that increased calcium can lower LDL (bad) cholesterol.

The Ex Factor

You know you can’t get through a health book without a mention of the “ex” factor, or exercise. Physical activity directly ties in to the conversation about bone and muscle health. Physical exercise, especially the weight-bearing kind, puts healthy stress on your bones to keep them strong and force them to be even stronger. It also works the muscles that keep you nimble and quick on your feet.

Young women and men who exercise regularly generally achieve greater peak bone mass than those who do not. Exercising allows us to maintain muscle strength, coordination, and balance, which in turn helps to prevent falls and related fractures. This is especially important for older adults and people who have been diagnosed with osteoporosis. The exercise you choose needn’t be complicated, boring, or overly challenging or demanding. The best exercise for your bones is the kind that forces you to work against gravity, even if its’ simply by working against your own body weight, as is the case for modern forms of yoga, mat Pilates, and the use of a resistance band. Other examples include weight training, hiking, jogging, climbing stairs, tennis, dancing, and of course, walking. It’s the constant pounding on the ground that translates to better muscle strength in the hips and lower back, maintaining or increasing bone density. These are the two places that are at highest risk for fracture.

Colon Cancer

Cancer of the colon and its neighboring area, known sometimes as colorectal cancer, affects both men and women. Like breast cancer and prostate cancer, colorectal cancer is seen much more frequently than skin cancers and is much more deadly. About 150,000 Americans are told each year that they have colon cancer, and about 35 percent of these will die of it. There are many contributing factors in why someone gets colon cancer, but the most commonly acknowledged one is diet. Diets high in fat and nonorganic non-grass-fed red meat are especially dangerous. Other diets, such as high in fruits, vegetables, and other natural raw and organic foods, help prevent colon cancer.

A study published in the Journal of Clinical Oncology in 2008, conducted by lead researchers Dr. Kimmie Ng of the Dana-Farber Cancer Institute in Boston found that high blood levels of vitamin D increased colon cancer patient’s survival rate by 48 percent. In this study, Dr. Ng and her team collected data on 304 patients who had been diagnosed with colon cancer between 1991 and 2002. Everyone in the study had their vitamin D blood levels measured a minimum of two years before being diagnosed with the disease. The patients were tracked until they died or until the study ended in 2005; 123 patients died, 96 of them from colon or rectal cancer during the follow-up period. Dr. Ng and her team found that the patients with the highest vitamin D levels were 39 percent less likely to die from colorectal cancer than the patients who had the lowest levels.

These findings are consistent with dozens and dozens of other observations that have been made in the past decade, including those by Dr. Cedric Garland. His lab reports that you are three times less likely to die from colon cancer if you have healthy levels of vitamin D in your bloodstream.