The Sodium Controversy
Remember – everything thing you hear in the news you should take with a grain of salt, well now you can have it with two grains of salt.
In May, the Institute of Medicine (IOM) released a report that reversed the past 40 years of dietary advice about sodium. They reviewed all of the research and clinical studies and concluded that the evidence does not support the current dietary guidelines for sodium intake. So let the controversy begin!
The problem for nutrition science is the public, and certainly the news media, wants specific answers, and they want the answers today. So nutrition and medical researchers are put in the position of making recommendations that are often not much better than a best guess. Let’s look at the facts about sodium.
Ordinary table salt is made up of two chemicals, sodium and chloride. Both are essential nutrients required in our body, and we must get them from our diet. All animals including humans require a daily supply of sodium and chloride or they will die within days. If we look across all cultures, lifestyles and diet patterns, humans consume between 3.0 and 3.5 grams of sodium daily. So self-selection of food suggests that the human body wants about 3.0 grams of sodium each day. Americans consume an average of 3.4 grams/day (often referred to as 3400 milligrams). A level teaspoon is equal to about 5.0 grams, so 3.0 grams is not very much. (Note – sodium and chloride each make up about ½ of salt, so 3.0 g of sodium is equal to about 6.0 g of table salt)
The current Dietary Guidelines recommend that all adults should reduce sodium consumption to less than 2.3 grams/day; and anyone over 51 years of age, all African-Americans, and anyone with high blood pressure should restrict sodium below 1.5 grams/day. Those guidelines are very restrictive to normal food choices and there is no evidence to support the numbers. The numbers are mostly a guess.
The emphasis on sodium stems from desire to control heart disease. The three most important factors in risk for a heart attack or stroke are family history (your genetics), smoking and blood pressure (BP). Elevated BP or hypertension is a major risk factor and must be treated. Dietary surveys found high salt intakes were often associated with high BP, and clinical studies showed that reducing salt intake reduced BP. The problems arise with defining how much salt is healthy and who will get any benefit.
For years, physicians have known that lowering blood volume will reduce BP. With less fluid in the pipes, the heart produces less pressure with each beat to move the blood. There are two ways to reduce blood volume. One approach is to drink less water. That’s called dehydration and that’s not very good for you. A decrease in just 4% of blood volume will decrease physical strength by more than 20%. A decrease of 7% of blood volume, and you’ll pass out. So dehydration is not a great option.
A second approach is to lower salt intake. Blood is basically a salty fluid and the body needs it that way for a lot of complex reasons. If you ever go into the hospital, one of the first tests doctors run is to check the sodium (Na), chloride (Cl) and potassium (K) concentrations in your blood and immediately start an IV bag to adjust these salts to the ideal levels. Under normal conditions, the body uses the kidney to maintain the salt levels. The kidney is like a complex dialysis machine that is constantly checking for the right levels of water, salts and blood pressure. Any time the balance needs adjustment, the body triggers an array of hormones (ie. renin, angiotensin, aldosterone, and antidiuretic hormone) to correct the balance. If you drink lots of water, the urine volume increases and the salt content becomes more dilute as the body protects the salt needed in the blood. If you’re not drinking enough and become dehydrated, urine volume goes down and the urine becomes more concentrated. This is what diuretics do. They force the kidney to lose more salt and along with the salt goes more water that reduces blood volume and BP. Diuretics work to reduce BP but they work by producing dehydration. So the trade-off is reduced BP compared with abnormal fluid balance. Every drug has side effects. Okay, that’s the physiology, so let’s get back to the recommendations and the numbers.
The AVERAGE sodium intake is about 3.4 grams but some people have intakes above 6.0 grams/day while others are below 2.0 grams/day. It’s clear from years of clinical research that individuals with high BP combined with sodium intakes above average will get beneficial effects on BP by reducing salt intake. So if your diet is largely based around eating potato chips, French fries, pizza and canned soups, you probably need to make changes. The problem comes from the big extrapolation that adults with normal BP or adults with normal salt intakes will get health benefits from lowering salt intakes down to 2.3 grams or even 1.5 grams. Research shows that these extreme diets will cause an immediate drop in BP, but the body immediately starts to correct this imbalance by triggering the array of “rescue hormones” including aldosterone and antidiuretic hormone to protect you from dehydration. The scientists on the IOM committee concluded that there was no proven benefit to long-term health of these extremely low salt recommendations, and that there were potential risks to creating this imbalance. Daily intake of 3.0 grams of sodium is okay – really! You don’t have to feel guilty.
The more natural and healthy solutions to optimal BP are reducing dietary carbohydrates and increasing protein (insulin is a significant cause of high BP), reducing body weight and especially abdominal body fat, increasing vegetable intake to get more potassium, calcium and magnesium, and increasing physical activity, plus the more recent discovery of the benefits of improving nitric oxide. Qivana uses the natural approach with the METABOLIQ Lifestyle and PRIME. METABOLIQ was designed to balance the carbohydrate and protein intakes to reduce the risks of insulin; METABOLIQ triggers loss of body fat and helps with weight management; and METABOLIQ increases use of SmartCarb vegetable intake. PRIME uses the novel discoveries of beetroot and hawthorn berries as a natural approach to increasing nitric oxide production. BP is a serious risk factor for heart disease and stroke and it must be controlled. Fortunately, life presents us with opportunities for natural approaches to good health.
For your health, Dr. Donald K. Layman CSO, Qivana
Dr. Donald K. Layman is Professor Emeritus of Nutrition in the Department of Food Science and Human Nutrition at the University of Illinois. With more than 33 years of teaching and research experience, Dr. Layman has numerous awards and recognitions, including awards from the American Society for Nutritional Sciences, the National Institutes of Health and the Nutrition and Metabolism Society.
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