All entries tagged with “cardiovascular”
Vitamin D and Your HeartJust like haircuts and clothing, vitamins will from time to time become fashionable in maintaining health and preventing disease. Vitamins E, C and folate seem to have had their time and the focus lately has been on Vitamin D. The body’s requirement for Vitamin D is met in two ways – 95% is derived from the exposure to ultraviolet B radiation, which creates Vitamin D in the skin, while the remainder is obtained from foods. Many foods are fortified with Vitamin D including dairy products, cereals and orange juice. A potent natural source of Vitamin D is oily fish such as salmon, mackerel, tuna and sardines. Depending on the normal cut-off value for Vitamin D, it is estimated that 25-60% of the United States population is deficient in Vitamin D. Risk factors for deficiency include increased distance from the equator ( the atmosphere filters the needed ultraviolet radiation), lack of sunshine, darker pigmentation, smoking, obesity, physical inactivity and certain medications. Originally recognized for its importance in bone development, it has recently been discovered that Vitamin D acts more like a hormone in that there are Vitamin D receptors located throughout the body; including white cells, nerve cells, heart cells and the pancreas cells that release insulin. The exact role of Vitamin D in these non-bone cells is the subject of much current research. Most of the available data on the consequence of Vitamin D deficiency is derived from population based observation studies in which Vitamin D levels were correlated with various outcomes including cardiovascular disease and death. For example, in the NHANES III study, patients with the lowest 25% of Vitamin D levels had a 26% higher risk of dying in the 9 years of follow up. In the Intermountain study, patients with low Vitamin D levels had an increased risk of having diabetes, high blood pressure, high cholesterol and also an increased risk of heart attack or stroke. Another recent study looking at patients who came to the hospital with heart attacks found that 96% were deficient in Vitamin D. While these are interesting findings they do not answer the key question- does giving Vitamin D reduce these risks? That requires a prospective, randomized double blind trial in which neither patients or investigators know who is receiving Vitamin D. One obvious obstacle is that it is impossible to restrict Vitamin D in the placebo arm as sunlight is everywhere. Nonetheless, about 18 studies have attempted to do just this with varying results. When the studies are pooled together, Vitamin D does appear to impart a modest (7%) reduction in the risk of dying. Is there any harm in having too much Vitamin D? The answer at this time appears to be yes. The population based studies demonstrate that there is a “U shaped” curve for Vitamin D, meaning that at high levels it may increase the risk of dying. There is currently a major trial sponsored by the NIH called the VITAL study which seeks to answer many of these questions. Until those results are released it seems prudent to try and maintain Vitamin D levels in a physiologic range by consuming foods rich in Vitamin D, living a healthy lifestyle as well as ensuring adequate exposure to sunlight. 
Simplifying Cholesterol Numbers: “All that is not good is bad”
Those of you that have been checking and following your cholesterol numbers over the years have probably felt confused at some point about what the optimal values are or even what values to follow. The basic components of the cholesterol panel have not changed- total cholesterol is a sum of HDL (good cholesterol) + LDL (bad cholesterol) and Triglycerides. What has changed is which of these entities is the primary focus of our attention and where to set the goals for these values. Initially, patients were told that an ideal cholesterol level meant a total cholesterol less than 200. This approach fell out of favor as it was then appreciated that HDL cholesterol was protective and that high levels of HDL (which raised the total cholesterol) was associated with a lower risk of heart disease. Likewise, patients with low HDL (which would result in a lower total cholesterol) were at increased risk of heart attack. The focus then shifted to primarily worrying about the level of LDL cholesterol as many large studies suggested that the level of LDL cholesterol was the most important predictor of a person’s risk for heart disease. Once there was general consensus that the LDL was the most important measure, researchers sought to define the optimal level of LDL cholesterol. The optimal level of LDL for patients with heart disease has dropped from 130 to 100 and now to 70 based on data that each subsequent reduction further reduces the risk for heart attack. However, there are several problems with an “LDL-centric” approach to cholesterol. First, patients with low LDL are still at some risk of heart attack which has been termed “residual risk” suggesting that LDL is not the whole story. Second, there is currently an epidemic of patients who are overweight with diabetes (“metabolic syndrome”) who are clearly at high risk for heart disease, despite a relatively normal LDL. In addition to normal LDL these patients will typically have elevated triglycerides and low HDL. An idea that is gaining traction in the cardiovascular prevention community is to simply dichotomize cholesterol into good and bad. In other words, if HDL is the only good cholesterol then everything else (termed “non-HDL” cholesterol) must be increasing the risk of heart attack. Non-HDL also includes cholesterol particles that are not routinely assessed like very low density LDL or VLDL. In fact, many large studies have already proven that non-HDL is actually better than LDL at predicting the risk of heart disease. In terms of what the ideal non-HDL level should be, guidelines suggest that a level 30 points higher than your goal LDL (which can be determined by your doctor) is probably optimal.
Listen to 120,000 people tell you how to avoid obesity
A recent study in the New England Journal of Medicine looked at over 120,000 people who were healthy and not obese at baseline and followed them for up to 20 years. The study participants were watched very closely with regard to what they ate, what they drank and how they spent their time. Slow and Steady: The first finding from the study is that weight gain on average is insidious. Participants added slightly less than one pound per year which makes it difficult to detect in the short term but explains how a person could add 10 or 20 pounds without noticing. Potatoes Found to Be the Worst: Of all of the foods associated with weight gain, French fry and potato chip consumption was associated with the largest weight gain (7 and 3 pounds over 4 years respectively). Sugar sweetened beverages were also found to add pounds. Additionally, processed and unprocessed meats encouraged weight gain. While sweets and desserts contributed to weight gain, their relative contribution was modest. Yogurt Best to Help Lose Weight: As expected, increased intake of fresh fruits and vegetables was associated with net weight loss as was whole grains and nuts. However, the biggest weight loss was seen in patients who ate yogurt. This was somewhat of an unexpected finding and may relate to the pro-biotic effects of yogurt. Other types of dairy products (both whole fat and low fat) were relatively weight neutral. Exercise More, Watch Less TV and Sleep Just Right: All patients who exercised enjoyed some relief from weight gain and the biggest reduction was seen in those with the most exercise. Regarding television, every hour spent watching television each day added 0.31 pounds. Interestingly, it appears that there is a “sweet spot” for sleep that is 6-8 hours per night which is associated with weight loss. People who slept more than 8 hours or less than 6 saw weight gain. What About Alcohol? There was an increase in weight of 0.41 pounds for every drink per day. This reinforces the concept that alcohol can be healthy at low levels (1-2 drinks per day) but harmful above that. So what are the take –home messages from this enormous observational study? Eat more yogurt, avoid potatoes, sleep 6-8 hours every night and only watch TV while you are on the treadmill.
Cardiac Rehab Slashes Risk of Dying by 50%In the early days of cardiology, patients with heart disease were advised to rest for weeks to months after a heart attack. In the 1960s the prevailing theory was challenged and the modern concept... More »
Are You Healthy Enough to Exercise?At first glance the question seems kind of ridiculous. You are exercising to get healthy so how could exercise itself NOT be healthy? The truth is that there is some risk of having a heart attack... More »
eat those eggsAccording to the U.S. Government's latest guidelines, one egg per day does not result in increased blood cholesterol levels. Nor does it increase the risk of cardiovascular disease in normal people. What... More »
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