Selected Health News Articles—Summary and Comments by Dr. Grossman
As many of you know, I try to practice “evidence-based medicine,” and prescribe therapies which have been demonstrated to be effective, in well-designed research trials. Recently of note is an accumulating body of research on vitamin D that leads me to favor supplements containing this vitamin. There is also new information regarding salt in the diet and the treatment of heart conditions with statins: Here are the details:
Vitamin D: In contrast to the bad news on folate above, evidence is accumulating that Vitamin D deficiency is common in the adult population of the United States and Europe, and is associated with more than just bone disease. Deficiency of vitamin D causes rickets in children and osteomalacia in adults. However, there is a fair body of evidence that vitamin D deficiency predisposes to hypertension, and can make control of high blood pressure difficult. Go to http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2010/01/09/MN8T1BEG4V.DTL to read an article on Vitamin D that appeared in the San Francisco Chronicle, which I liked (occasionally they get things right!) My advice is to get your vitamin D level measured (a simple blood test) and if it is low, take supplemental vitamin D, or increase your intake of foods rich in vitamin D (e.g., salmon, of course!)
Other research of potential interest regarding prevention of heart and vascular disease has been coming out steadily. There has been much attention in the last few months focused on daily dietary salt intake. Common cooking or table salt is 100 percent sodium chloride, and 1 gram of salt contains 400 mg of sodium. So-called “sea salt” is 86 percent sodium chloride, and only 1 percent potassium. In contrast, most salt substitutes (e.g., Morton’s Salt Substitute) are nearly 100 percent potassium chloride, and contain no sodium. Potassium actually lowers blood pressure, and counteracts the effect of sodium in most tissues in the body.
Confirmation of the important role that excess dietary salt has been published in the New England Journal of Medicine in January 2010, in an article entitled “Projected Effect of Dietary Salt Reductions on Future Cardiovascular Disease.” That study was carried out here at UCSF, and the first author (Dr. Kirsten Bibbins-Domingo) is Co-Director of the UCSF Center for Vulnerable Populations at San Francisco General Hospital. The article reported that an average man in the United States consumes 10.4 grams of salt daily, while an average woman consumes 7.3 grams of salt per day. The recommended daily maximum for most adults (those age 40 or older, and especially if there is high blood pressure) is less that 4 grams of salt per day. If a population-wide reduction in salt (sodium) intake of 3 grams per day (1200 mg sodium) could be obtained, still well above the official recommended salt intake, the study estimated that there would be a reduction in the annual U.S. incidence of stroke from 98,000 to 66,000 cases/year, and a reduction in the incidence of myocardial infarction or heart attack from 153,000 to 99,000 cases per year.
This degree of modest reduction in salt intake should be possible, according to the authors, especially if achieved in the food processing industry where foods of very high salt content (e.g., tomato sauces, soups, processed meats such as sausages, hams, bacon, breads, cheeses, etc.) are ubiquitous.
Finally, reports continue to appear on unexpected benefits of statins (such as simvastatin or Zocor, pravastatin or Pravachol, atorvastatin or Lipitor, or rosuvastatin or Crestor). A study published in November 2009 in JAMA of over 130,000 subjects in the United Kingdom reported that people taking statins had a substantial reduction in the incidence of gallstone disease and need for cholecystectomy (gallbladder removal) compared to those not on a statin. There is some logic to this, since most gallstones are made of cholesterol, and if the enzymes producing cholesterol in the liver are blocked, it stands to reason that there will be less cholesterol to excrete in the bile.
A study reported in the New England Journal of Medicine entitled “A Randomized Trial of Rosuvastatin in the Prevention of Venous Thromboembolism” reported that patients randomly assigned to receive rosuvastatin (Crestor) had 55 percent fewer attacks of deep-vein thrombosis (serious blood clots in the legs) than those assigned to receive placebo. The mechanism whereby statins achieved this beneficial effect are not understood, but may have something to do with antithrombotic (anti-clotting) effects of the drugs.
