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sodium intake

Lowering sodium intake may have far-reaching benefits, and it is certainly achievable. Stock photo
High sodium: potassium ratio increases cardiovascular risk

By David Dunaief, M.D.

Dr. David Dunaief

We need sodium in our diets in modest amounts; however, many Americans overconsume it. Meanwhile, potassium, which we also need, is underconsumed.

More than 90 percent of people consume far too much sodium, with salt being the primary culprit (1). Sodium is found in foods that don’t even taste salty. Bread and rolls are the primary offenders. Other foods with substantial amounts of sodium are cold cuts and cured meats, cheeses, pizza (which has both bread and cheese), fresh and processed poultry, soups, meat dishes, pastas and snack foods. Foods that are processed and those prepared by restaurants are where most of our consumption occurs (2).

By contrast, only about 2 percent of people get enough potassium from their diets (3). According to one study, we would need to consume about eight sweet potatoes or 10 bananas each day to reach appropriate levels. Why is it important to reduce sodium and increase potassium? A high sodium-to-potassium ratio increases the risk of cardiovascular disease by 46 percent, according to the study, which looked at more than 12,000 Americans over almost 15 years (4). In addition, both may have significant impacts on blood pressure and cardiovascular disease.

To improve our overall health, we need to tip the sodium-to-potassium scales, consuming less sodium and more potassium. Let’s look at the evidence.

Reduced sodium

Two studies illustrate the benefits of reducing sodium in high blood pressure and normotensive (normal blood pressure) patients, ultimately preventing cardiovascular disease, including heart disease and stroke.

The first used the prestigious Cochrane review to demonstrate that blood pressure is reduced by a significant mean of −4.18 mm Hg systolic (top number) and −2.06 mm Hg diastolic (bottom number) involving both normotensive and hypertensive participants (5). When looking solely at hypertensive patients, the reduction was even greater, with a systolic blood pressure reduction of −5.39 mm Hg and a diastolic blood pressure reduction of −2.82 mm Hg.

This was a meta-analysis (a group of studies) that evaluated data from randomized clinical trials, the gold standard of studies. There were 34 trials reviewed with more than 3,200 participants. Salt was reduced from 9 to 12 grams per day to 5 to 6 grams per day. These levels were determined using 24-hour urine tests. The researchers believe there is a direct linear effect with salt reduction. In other words, the more we reduce the salt intake, the greater the effect of reducing blood pressure. The authors concluded that these effects on blood pressure will most likely result in a decrease in cardiovascular disease.

In the second study, a meta-analysis of 42 clinical trials, there was a similarly significant reduction in both systolic and diastolic blood pressures (6). This meta-analysis included adults and children. Both demographics saw a reduction in blood pressure, though the effect, not surprisingly, was greater in adults. Interestingly, an increase in sodium caused a 24 percent increased risk of stroke incidence but, more importantly, a 63 percent increased risk of stroke mortality. The risk of mortality from heart disease was increased as well, by 32 percent.

In an epidemiology modeling study, the researchers projected that either a gradual or instantaneous reduction in sodium would save lives (7). For instance, a modest 40 percent reduction over 10 years in sodium consumed could prevent 280,000 premature deaths. These are only projections, but in combination with the above studies they may be telling. The bottom line: Decrease sodium intake by almost half and increase potassium intake from foods.

Potassium’s positive effects

When we think of blood pressure, sodium comes to mind, but not enough attention is given to potassium. The typical American diet doesn’t contain enough of this mineral.

In a meta-analysis involving 32 studies, results showed that as the amount of potassium was increased, systolic blood pressure decreased significantly (8). When foods containing 3.5 to 4.7 grams of potassium were consumed, there was an impressive −7.16 mm Hg reduction in systolic blood pressure with high blood pressure patients. Anything more than this amount of potassium did not have any additional benefit. Increased potassium intake also reduced the risk of stroke by 24 percent. This effect was important.

The reduction in blood pressure was greater with increased potassium consumption than with sodium restriction, although there was no head-to-head comparison done. The good news is that potassium is easily attainable in the diet. Foods that are potassium-rich include bananas, sweet potatoes, almonds, raisins and green leafy vegetables such as Swiss chard.

Lowering sodium intake may have far-reaching benefits, and it is certainly achievable. We need to reduce our intake and give ourselves a brief period to adapt — it takes about six weeks to retrain our taste buds, once we reduce our sodium intake. We can also improve our odds by increasing our dietary potassium intake, which also has a substantial beneficial effect, striking a better sodium-to-potassium balance.

References:

(1) Am J Clin Nutr. 2012 Sep;96(3):647-657. (2) www.cdc.gov. (3) Am J Clin Nutr. 2012 Sep;96(3):647-657. (4) Arch Intern Med. 2011;171(13):1183-1191. (5) BMJ. 2013 Apr 3;346:f1325. (6) BMJ. 2013 Apr 3;346:f1326. (7) Hypertension. 2013; 61: 564-570. (8) BMJ. 2013; 346:f1378.

Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com or consult your personal physician.  

The effects of high sodium are insidious

By David Dunaief, M.D.

Dr. David Dunaief

By now, most of us have been hit over the head with the fact that too much salt in our diets is unhealthy. Still, we respond with “I don’t use salt,” “I use very little,” or “I don’t have high blood pressure, so I don’t have to worry.” Unfortunately, these are myths. All of us should be concerned about salt or, more specifically, our sodium intake.

Excessive sodium in the diet does increase the risk of high blood pressure (hypertension); the consequences are stroke or heart disease. Approximately 90 percent of Americans consume too much sodium (1).

Now comes the interesting part. Sodium has a nefarious effect on the kidneys. In the Nurses Health Study, approximately 3,200 women were evaluated in terms of kidney function, looking at the estimated glomerular filtration rate (GFR) as related to sodium intake (2). Over 14 years, those with a sodium intake of 2,300 mg had a much greater chance of an at least 30 percent reduction in kidney function, compared to those who consumed 1,700 mg per day.

Why is this study important? Kidneys are one of our main systems for removing toxins and waste. The kidneys are where many initial high blood pressure medications work, including ACE inhibitors, such as lisinopril; ARBs, such as Diovan or Cozaar; and diuretics (water pills). If the kidney loses function, it may be harder to treat high blood pressure. Worse, it could lead to chronic kidney disease and dialysis. Once someone has reached dialysis, most blood pressure medications are not very effective.

Ironically, the current recommended maximum sodium intake is 2,300 mg per day, or one teaspoon, the same level that led to negative effects in the study. However, Americans’ mean intake is twice that level.

Excessive sodium in one’s diet can increase the risk of high blood pressure, which can lead to a stroke or heart disease. Stock photo

If we reduced our consumption by even a modest 20 percent, we could reduce the incidence of heart disease dramatically. Current recommendations from the American Heart Association indicate an upper limit of 2,300 mg per day, with an “ideal” limit of no more than 1,500 mg per day (3).

If the salt shaker is not the problem, what is? Most of our sodium comes from processed foods, packaged foods and restaurants. There is nothing wrong with eating out on occasion, but you can’t control how much salt goes into your food. My wife is a great barometer of restaurant salt use. If food from the night before was salty, she complains of not being able to get her rings off.

Do you want to lose 5 to 10 pounds quickly? Decreasing your salt intake will allow you to achieve this goal. Excess sodium causes the body to retain fluids. 

One approach is to choose products that have 200 mg or fewer per serving indicated on the label. Foods labeled “low sodium” have fewer than 140 mg of sodium, but foods labeled “reduced sodium” have 25 percent less than the full-sodium version, which doesn’t necessarily mean much. Soy sauce has 1,000 mg of sodium per tablespoon, but low-sodium soy sauce still has about 600 mg per tablespoon. Salad dressings and other condiments, where serving sizes are small, add up very quickly. Mustard has 120 mg per teaspoon. Most of us use far more than one teaspoon of mustard. Caveat emptor: Make sure to read labels on all packaged foods very carefully.

Is sea salt better than table salt? High amounts of salt are harmful, and the type is not as important. The only difference between them is slight taste and texture variation. I recommend not buying either. In addition to the health issues, salt tends to dampen your taste buds, masking the flavors of food.

If you are working to decrease your sodium intake, become an avid label reader. Sodium hides in all kinds of foods that don’t necessarily taste salty, such as breads, soups, cheeses and salad dressings. I also recommend getting all sauces on the side, so you can control how much — if any — you choose to use.

As you reduce your sodium intake, you might be surprised at how quickly your taste buds adjust. In just a few weeks, foods you previously thought didn’t taste salty will seem overwhelmingly salty, and you will notice new flavors in unsalted foods.

If you have a salt shaker and don’t know what to do with all the excess salt, don’t despair. There are several uses for salt that are actually beneficial. According to the Mayo Clinic, gargling with ¼ to ½ teaspoon of salt in eight ounces of warm water significantly reduces symptoms of a sore throat from infectious disease, such as mononucleosis, strep throat and the common cold. Having had mono, I can attest that this works.

Remember, if you want to season your food at a meal, you are much better off asking for the pepper than the salt.

References:

(1) cdc.gov. (2) Clin J Am Soc Nephrol. 2010;5:836-843. (3) heart.org.

Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com or consult your personal physician.