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Sunday, December 29, 2013

Multivitamins CAN Protect Against Cardiovascular Disease and Cancer

Three recent studies published in the Annals of Internal Medicine questioned the benefits of multivitamin supplements and last week I debunked the one about brain function.

This week I take a closer look at the other two and explain why their flawed design led to questionable conclusions about cancer and cardiovascular protection.

The study "Oral High-Dose Multivitamins and Minerals After Myocardial Infarction" aimed to assess whether multivitamin supplements reduced the risk of disease and death in adults over the age of 50 after having a heart attack. In this study, researchers measured how long people lived before they had another heart attack, suffered a stroke, were hospitalized for chest pain, required heart surgery (bypass, stent, or angioplasty), or died from any cause.

They found that compared to people taking a placebo, those taking multivitamins had an 11 percent lower risk of suffering any of these events and an 18 percent lower risk of dying from cardiovascular disease. However, the researchers dismissed these benefits because the risk reduction was less than 25 percent and not statistically significant, which simply means that they were less than 95 percent sure that the effects didn't happen by chance. It doesn't mean that there was no benefit at all.

One problem with this study was that there were more people with diabetes taking multivitamins than taking the placebo. Because diabetes is one of the biggest risk factors for developing cardiovascular disease, people taking the multivitamins were already more likely to develop cardiovascular disease whether they took the supplements or not.

Other problems with this study include the amount of vitamin D and the form of vitamin E in the multivitamins. They contained only 100 International Units of vitamin D while the optimal intake for adults is 1,000 to 2,000 I.U. Vitamin D is essential for heart health and low levels have been linked to developing and dying from cardiovascular disease.

Vitamin E naturally exists in eight related compounds, four tocotrienols and four tocopherols, each designated alpha, beta, gamma, and delta. The multivitamins included only one of these compounds, alpha tocopherol. Studies show that supplementing alpha tocopherol alone depletes the other compounds including gamma tocopherol, which has been shown to reduce rates of cardiovascular disease and death.

The other multivitamin study "Vitamin and Mineral Supplements in the Primary Prevention of Cardiovascular Disease and Cancer" looked at whether multivitamins reduced the risk of cardiovascular disease and cancer.

Regarding cancer prevention, researchers actually found that men taking multivitamins had a statistically significant 7 percent lower risk of developing cancer. The same benefit was not found in women. While more studies should be undertaken to investigate the difference, it isn't correct to conclude that there was no benefit.

Regarding cardiovascular protection, investigators looked at two trials, one involving Centrum Silver (I discussed the problems with this low-potency multivitamin containing harmful chemicals last week) and the other utilizing five individual nutrients (vitamin C, vitamin E, beta-carotene, selenium, and zinc).

In both cases, zinc was supplemented without copper. There was none at all in the five nutrient study and while Centrum Silver does contain copper, for the majority of the trial it was given in the form of cupric oxide which cannot be absorbed by humans. (Since then it has been replaced with cupric sulfate).

Studies show that taking zinc for long periods of time can deplete copper, and that copper deficiency increases the risk of cardiovascular disease, specifically ischemic heart disease and problems with blood pressure control and cholesterol metabolism (along with osteoporosis and poor blood sugar control).

Fortunately, other, more scientifically sound research studies show that multivitamins do protect against developing and dying from cardiovascular disease and cancer. For example:
  • The Physician's Health Study II, a large-scale, randomized, double-blind, placebo-controlled trial followed nearly 15,000 male physicians 50 years and older, including more than 1,300 men with a history of cancer for 14 years. Researchers found that daily multivitamin supplementation reduced the risk of having a fatal heart attack by 39 percent. Those taking multivitamins also significantly reduced their risk of cancer, with an 8 percent reduction in cancer incidence and 12 percent fewer cancer deaths.

In an ideal world, the vitamins and minerals we need would come from food. But in the real world, it’s almost impossible to get all of the nutrients our bodies need from diet alone. There are several reasons and some of them include:
  • Modern-day lifestyles, prescription medications, and chronic illnesses all increase our needs for nutrients but foods today are significantly less nutritious than the wild ones that were available to our ancestors
  • Industrial-farming methods like growing monocultures and using chemical fertilizers have depleted nutrients in soil, and if the nutrients aren’t available for plants to absorb them, we don't ingest them
  • We’ve selected and engineered plant species for their appearance and shelf life, not for their nutritional content
  • We pick fruits and vegetables before they’re ripe (unripe produce has significantly less nutrients than mature produce) and ship them long distances, which depletes nutrient stores even further
  • Air pollution and rising levels of carbon dioxide in the atmosphere reduce the nutritional content of the plants we eat
  • A large portion of the foods we eat have been processed and the manufacturing methods used to make them destroy vitamins

Multivitamins can compensate for what’s missing, so think of them as health insurance. Formulas and quality vary greatly from one brand to another and what's inside is as important as what isn't. Many multivitamins contain cheap, inactive forms of nutrients that are not well-absorbed or they contain contaminants, fillers, binders, and flowing agents that can have adverse effects.

Read about what I look for in multivitamins on page 89 of my new book, The Prediabetes Detox, or get individualized recommendations from your naturopathic doctor.

Unlike other medical practitioners, naturopathic doctors have extensive training in prescribing supplements like vitamins and minerals and they are knowledgeable in potential interactions between natural medicines and prescription medications.

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