May 2, 2016

Salt Continues to Be Controversial

The shame of this is the lack of science being applied to salt needs of the body. Each side proclaims their agenda, but cannot show any definitive science to prove their claims. This article is one of the better articles and applies reason in place of lack of science.

If you have tried to find science to help you figure the best salt intake, you have probably read some of the controversy. "The less the better,” has been the message for the last 30-40 years. That dogma is not being challenged. This is also the reason that the low carb diet may be affecting the amount of salt we need. To understand some of this, we need to examine the controversy.

In July 2015, before the 2015 Dietary Guidelines were released, the Guidelines for Americans say that the “general population” should restrict their sodium intake to 2300 mg (about a teaspoon of salt). However, about half the population is not apparently in the "general population", as people over 50, African-Americans, and others in groups at a risk for high blood pressure are told to restrict their intake to 1500 mg. The American Heart Association maintains that everyone should stay at 1500 mg.

However, no one does this, as this is very difficult to do! We could have a long conversation as to whether it is a good idea to recommend something that only a small number of people worldwide can attain.

But instead, let's turn to the science). The reason for recommending salt intake is that there is an association between eating a lot of salt and high blood pressure. However, there are a couple of caveats:

1) While going from a high-salt intake to a moderate-salt intake does tend to lower blood pressure, for most people going from a moderate intake to a low intake does very little good.

After looking into the matter, in 2013 the Institute of Medicine reported that there is no evidence that reducing sodium intake below 2300 mg provides benefit. Other recent analyses have shown little correlation in the general population between blood pressure and salt intake, although there are definitely people who do benefit, which brings us to:

2) The people who benefit the most from salt reduction are what is called "salt sensitive", which is thought to be about 10-20% of the general population.

Older people, African-Americans, and people who have high blood pressure are more likely to be salt sensitive.

If you are salt sensitive, it is probably good to know it, although the only real way to find out is to wait until you have high blood pressure and then see if reducing salt helps. But, there is actually evidence that people who are salt sensitive are at a greater risk for heart disease even if their blood pressure is kept normal. One thought is that whatever is causing the salt sensitivity may be causing inflammation and possibly other bad effects. There is much to learn about this.

What is considered a moderate salt intake? There is a lot of controversy on this point! Some experts say that the average amount of sodium people tend to eat (around 3500 mg, or 3.5 grams) is way too much, while others say that this is the very definition of moderate.

If you cook from scratch and mostly eat at home, you are probably eating a moderate or lowish amount of salt by any definition. But if you eat out a lot and/or eat prepared and packaged foods, the grams can add up fast! According to the Centers for Disease Control and Prevention, the average person in the United States gets about 3/4 of their sodium from restaurants, prepackaged, and processed foods, while only 5% is added during home cooking and 6% from the salt shaker at the table.

Okay, now we need to ask about what are the dangers from too little salt. There is little research about this, but some observational studies have shown increased "cardiovascular mortality" or "all-cause mortality" for people eating a low-salt diet. However, complicated interactions can always be in the mix, for example, sick people may eat less food, which means they eat less salt.

Why is it dangerous to eat too little salt? Blood and many other bodily fluids (lymph, sweat, and fluid around our organs) are fairly salty, for good reasons. Our bodies use salt in many ways, and it is easy to imagine that things could go awry if we don't have enough of it. One of the more interesting observations is that a low-salt diet could increase insulin resistance in the muscles of some people. The researchers of the diabetes study point out that interference in metabolic and neurohormonal pathways that could result from a low-salt diet, at least in some people, but admit that we know very little at this point.

Could eating a low-carb diet impact our need for salt? Some experts think so in some people. Particularly in the first two weeks of a very low-carb (ketogenic) diet, the body lets go of a lot of water, and some electrolytes such as sodium and potassium along with it. Some physicians who are familiar with working with low-carb diets in their patients actually advise their patients to consume more salt during this time to help mitigate the "Atkins flu," i.e., feeling sickly in the first week or so. They often advise drinking a couple of cups of bullion or broth each day during this time.

Other experts, notably Stephen Phinney and Jeff Volek, feel that people on long-term ketogenic diets may need more salt on an ongoing basis, particularly if they are athletes or very active. They point to evidence that people on ketogenic diets tend to excrete more sodium. In The Art and Science of Low Carbohydrate Living, they advise that such people add 2-3 grams of sodium to the diet each day, particularly if they are feeling lightheaded or poorly with exercise.

As those of us who benefit from low-carb diets know very well, recommendations from the government or large health organizations are not always the best for the individual! It's up to you to find out what works for you. Make sure your blood pressure gets checked. Stay away from processed foods. If your blood pressure is high, make sure you're following a healthy low-carb diet, which has been shown to help normalize blood pressure for many people. If that doesn't do the job, try cutting back on salt.


David Mendosa said...

Great advice, Bob! Especially where you write that each of us has to determine for ourself if we are salt sensitive or not. I know from my own experience that I never restricted the amount of salt that I use and have never had high blood pressure. In fact, my blood pressure when tested by a nurse in a doctor's office is usually about 60 over 100.

Bob Fenton said...

Thanks David! I am on the salt sensitive side. I really know it when I consume too much salt. Even with BP medication, my blood pressure goes up.