How do you feel about conflicting advice? We hear from many readers that they get confused or frustrated when they get health or nutrition advice that is exactly the opposite of counsel they had been trying to follow for months or years. One reader expresses this sentiment for many others;
Trying to Deal with Conflicting Advice:
Q. I am fed up with medical flip-flops. Whether it is hormone replacement therapy, calcium supplements, eggs or salt, first we get told one thing and then doctors change their minds. In the meantime, we consumers are left wondering what to believe and whom to trust. I am still baffled by whether salt is as bad as I have always been told.
A. We understand how hard it is to make sense of contradictory evidence from medical research. You are right that there have been major reversals regarding eggs, calcium and salt, among other topics.
Salt Is Complicated:
Salt is another hot-button issue. An analysis of randomized controlled trials found that reducing sodium intake lowers blood pressure modestly (Journal of the American College of Cardiology, Feb. 18, 2020). On the other hand, sodium restriction also raises cholesterol, triglycerides and stress hormones.
An analysis of two cohorts with a total of 28,880 people found that over seven years both those consuming the least and the most sodium were at greater risk of dying (Journal of the American Medical Association, Nov 23, 2011).
Another prospective study (BMJ, March 13, 2019) showed that
“Combined moderate sodium intake (3-5 g/day) with high potassium intake is associated with the lowest risk of mortality and cardiovascular events.”
This isn’t to suggest that people should be increasing their salt intake, but not everyone needs to cut back. Clearly, it can be difficult to sort out the conflicting advice.
One reader wrote:
“Not enough salt in my diet makes my muscles cramp with even modest exercise. I rarely eat processed foods, so there are times when I don’t get enough sodium.”
To read more about the scientific data on the salt controversy, check out this link.
Conflicting Advice About Eggs:
Back in the 20th century, American physicians were told that cholesterol was the enemy. They passed that information on to their patients with strong recommendations to avoid eggs, butter, cheese and shrimp. All these foods are high in cholesterol. Nuts were also discouraged because of their fat content.
Today, this advice seems out of touch. It’s hard to believe that tens of millions of Americans changed their dietary habits based on opinion rather than scientific evidence.
Cereal vs Eggs for Breakfast:
Nutrition experts now acknowledge that substituting highly processed cold cereal instead of eggs was not a good tradeoff. For one thing, many of the most popular cereals are high in sugar and refined flour. Such foods can raise blood sugar quickly and contribute to a mid-morning slump.
Eggs, on the other hand, are a great source of protein and tend to be digested more slowly. They don’t make blood sugar spike. Scientists still can’t agree whether people who eat eggs are at greater risk for heart disease. Some evidence suggests that egg consumption might even reduce the risk of coronary artery disease (American Journal of Medicine, Jan. 2021). Large cohort studies over decades indicate that people eating an egg a day are at no higher risk of cardiovascular problems than those who avoid eggs (BMJ, March 4, 2020). So, are eggs good or bad?
One reader described her breakfast habit:
“I eat three eggs every morning for breakfast. I upped it from two eggs a couple of years ago when I was approaching age 80. Older people have to make sure we get enough protein, and there are many other benefits to eggs.
“For some reason there has been a bias against eggs in medicine. That has harmed people’s health, as many have been scared away from eggs and eat cereal and pancakes and toast for breakfast instead of protein foods. I discovered at age 11 that eggs were the only breakfast food that kept me from almost collapsing with hunger mid-morning at school, and I’ve continued to eat eggs almost every day of my life. At my advanced age I am healthy and take no pharmaceuticals.”
Another reader extended the conversation to include other formerly forbidden foods, such as butter:
“I never swallowed the ‘margarine is better than butter’ bilge. It’s not a theory because there was little to no research testing the assumptions. I have eaten eggs, butter, and full-fat dairy foods my whole life.
“According to my doctor, my cholesterol and triglycerides are perfect. My blood pressure at my last physical was 110/68. Some of this may be genetic, but not all of it. I don’t eat food that has ingredients unknown to humans before the 20th century.”
Nutrition scientists now know that the hydrogenated vegetable oils that were the main ingredient in margarine were counterproductive. Scientists at the Harvard School of Public Health estimated that 50,000 people died annually of heart attacks due to trans-fat containing margarine before 2004 when the FDA declared it harmful (New England Journal of Medicine, April 13, 2006).
Perhaps a good rule of thumb is to avoid foods that contain hard-to-spell chemicals and other compounds that have been developed to enhance flavor and shelf life. Also keep in mind that changes in scientific studies may result in conflicting advice. Checking to see whether advice is founded in strong evidence is a good first step to save yourself frustration.
Learn More:
You may want to listen to our interview with Dr. Aaron Carroll on how to deal with conflicting advice regarding nutrition. It is Show 1200: Making Sense of Changing Nutritional Guidelines.
