Can We Use Diet to Treat High Blood Pressure? A Review of the DASH Diet

/, Food Is Medicine/Can We Use Diet to Treat High Blood Pressure? A Review of the DASH Diet

How much sodium should we be consuming? The American Heart Association recommends limiting sodium consumption to no more than 2300mg daily, but ideally trying to keep this under 1500mg. Most Americans consume roughly 3400mg.

Almost universally, my patients tell me they do not add salt to their food. Adding salt isn’t the real culprit for most people! Most of our sodium intake comes from prepared and processed foods. Here is a list of the Top 25 foods that add the most sodium to your diet , according to the American Heart Association Website.(2)

Some of the foods on the list, such as chicken, might surprise you. While naturally, 4 ounces of chicken typically contains less than 100mg of sodium, much of the fresh chicken in grocery stores is injected with salt and water to make it appear more plump. A 4 ounce serving of “enhanced” poultry can contain 400-500mg of sodium, before even adding seasoning or sauces.(4) Many people are also surprised to find that just 3 ounces of plain shrimp can contain nearly 800mg of sodium according to the USDA Nutrient Database. This is in part due to treatment with a sodium rich solution in frozen shrimp, but even fresh shrimp can contain over 200mg for 3 ounces.

If you consider what many Americans eat as part of a “healthy” lunch, even a turkey sandwich with mustard and a slice of cheese can contain more than half of the daily recommended amount of sodium. 2 slices of whole wheat bread can add 300mg, 1 slice of processed cheese can add another 300mg, 4 ounces (1/4 pound) of turkey breast can add up to 1000mg, and a teaspoon of mustard is over 50mg. That’s over 1500mg without even touching a salt shaker!

To address this issue, in June 2016 the FDA sought to issue voluntary targets for reducing sodium in commercially processed and prepared foods. (5) Companies such as Nestle, General Mills, and Kraft Heinz responded by reducing the amount of sodium in their foods, and Dominos and Schwann’s reduced the sodium content of school lunches.

The DASH (an acronym for Dietary Approaches to Stop Hypertension) study was published in the New England Journal of Medicine in 2001. (1). The study sought to determine if consuming different levels of sodium along with a DASH diet versus a standard American diet (SAD) could lower blood pressure in people with and without a diagnosis of hypertension.

Why is it so important to limit sodium? In part because there is a strong correlation of sodium consumption and high blood pressure. We know that high blood pressure is a major risk factor for coronary artery disease and stroke, two of the most prevalent causes of death and disability in our country.

What is a DASH diet? This is essentially a plant-based diet, replete with bountiful fruits, vegetables, and whole grains, but one that still contains low fat dairy, poultry and fish. Red meat, sweets, processed foods, and sugary drinks are discouraged.

The study divided participants in both the DASH and SAD diets into one of three groups, consuming a low (1100mg), intermediate (2300mg), or high (3500mg) amount of sodium daily.

What they found was that at all 3 levels of sodium consumption, DASH diet participants had lower blood pressures than SAD participants. This effect was most pronounced in the group that consumed the most sodium, meaning that regardless of sodium intake, a plant based diet reduced blood pressure.

When comparing the SAD diet with high sodium consumption to the DASH diet with low sodium consumption, participants had up to an 11.5mmHg reduction in systolic blood pressure (top number) if they had high blood pressure to begin with, and up to a 7.1mmHg drop if they did not have high blood pressure entering the study. These findings are equivalent to what we might see with a blood pressure medication.

Consuming a whole-foods plant-based diet leads to lower blood pressure not only due to its naturally lower sodium content, but also due to eating larger amounts of potassium and magnesium, and consuming a variety of phytonutrients which lead to dilatation of the blood vessels.

 

References:

1. Sacks, Frank M., Svetkey, Laura P., et. al. Effects on Blood Pressure of Reduced Dietary Sodium and the Dietary Approaches to Stop Hypertension (DASH) Diet. N Engl J Med. 344, No 1, 3-10.

2. “Top 25 Foods That Add the Most Sodium to Your Diet”. https://sodiumbreakup.heart.org/top_25_foods_that_add_the_most_sodium_to_your_diet

3. “How Much Sodium Should I Eat Per Day?”  https://sodiumbreakup.heart.org/how_much_sodium_should_i_eat

4. “What are they pumping into your chicken?”. http://consumersunion.org/2011/10/what-are-they-pumping-into-your-chicken/).

5. “Sodium Reduction: Lowering Sodium in the Food Supply”. https://www.fda.gov/Food/IngredientsPackagingLabeling/FoodAdditivesIngredients/ucm253316.htm

 

2018-04-23T10:14:29+00:00