Welcome to Straight Talk on Health, I’m your host Dr. Chet Zelasko. Straight Talk on Health is a joint production with WGVU in Grand Rapids MI. I examine the world of health. Whether it’s research that makes the news, another miracle diet, or a new food fad, I look at the science behind them, and let you know whether it’s real or not. You can check out other things that I do on my website Drchet.com and sign up for my free emails.
When the American Heart Association (AHA) speaks, news organizations tend to report what they say and people tend to listen. It’s doubly true when they rank all the popular diets according to how they relate to heart health. Because we seem to live in a society based on the “ I see food, I eat food” diet, that can be meaningful. Here’s what a group of experts did to evaluate popular dietary approaches to diet and rank them according to AHA guidelines for a heart-healthy diet.
The AHA has ten dietary guidelines for eating a heart-healthy diet, such as “Eat plenty of vegetables and fruits” and “Choose healthy sources of proteins.” For the complete list, the scientific statement is open access on the AHA website.
Then, the panel selected the most popular diets in the U.S. such as the Mediterranean diet, the DASH diet, several versions of a vegetarian diet, low-fat, paleo, and ketogenic diet. They gave each diet a full point for following each of the AHA guidelines or partial points depending how closely they followed the guidelines.
This was not an arbitrary assignment by a panel of experts; they used the best information available to determine the best heart-healthy diet. Who got the highest score? Mediterranean? Vegan? Ketogenic? I’ll let you know in a moment in addition to my thoughts on the diets. One thing’s for certain: eat your fruits and vegetables. You may as well know that right now and start with that right now.
In assessing popular diets to find out which one follows the AHA heart-healthy dietary guidelines the best, the panel did a credible job. Instead of just using their expertise, which is substantial, they developed an objective way of assessing each popular diet. They did have one diet that received a point for each of the nine categories thus achieving 100%. That was the Dietary Approach to Stop Hypertension more commonly known as the DASH diet.
The researchers then assessed the dietary patterns and organized them into four tiers based on compliance with the AHA guidelines. I’ll break down the tiers for you.
Tier 1 includes the DASH diet, the Mediterranean diet, the pescatarian or fish as protein, and the ovo-lacto vegetarian diets. Ova-lacto means they will eat dairy and eggs which do not harm the animals; they are just a product of the animals. The primary reason that the DASH diet got a perfect score of 100%, was its ability to get protein from every source: plant proteins such as nuts and legumes, fish and seafood, low-fat or fat-free dairy, and the ability to use lean cuts of all meats. The other diets in Tier 1 either did not recommend proteins from all sources or did not emphasize reducing the amount of salt intake, a key element of the DASH diet. That's something that you would expect in the diet designed to reduce hypertension.
Let’s take a look at the next diet group, Tier 2. This included the vegan diet and other low-fat diets. Their strength, of course, is the emphasis on vegetables and fruits as well as whole grains, but they all seek to use plant-based protein which leaves limited options for protein intake. In addition, not eating any animal products doesn't mean that it's a healthy diet. You can still eat fried foods, an excessive amount of refined carbohydrates such as breads and pastas, and many other foods that are high in fat and ultra-refined carbohydrates. If you're going to be a vegan or follow a low fat diet, you have to be smart about it
Tier 3 included the very low fat diets as well as the low-carbohydrate diets. The reason these two are put together is the restriction on quality protein sources as well as whether people adhere to the diet at every meal. Some very low fat diets like the Esselstyn plan or the Ornish plan also restrict protein intake as well. The reason they are ranked so low is whether people will adhere to them in the real world.
Tier 4 The Paleo diet and very low carbohydrate diets such as the ketogenic diet received the worst scores; that means they fall into the category of not being heart healthy at all. The problem is the lack of long-term results. Yes, I've seen short term studies that suggest ketogenic diets may result in lowering cholesterol and blood pressure. I've also seen that within a year, people return to their prior see food, eat food diet and their numbers go back up including the weight that they've lost. As time progresses, we'll see whether the short-term results can be maintained by enough people to make it worthwhile to promote. But for now, based on the heart healthy criteria, it's a big no.
There were other considerations. The panel considered three primary issues. The first was how easy it would be to facilitate patients to adapt to the particular diet. To me, the strength of the DASH diet and to some degree the Mediterranean diet is the variety of proteins that can be used. When you get into the very low fat and the very low carbohydrate diet, the restrictions can become overwhelming for most people.
They also considered the challenges for the consumers. In my experience, there are always going to be questions about what could be included in any dietary approach, whether it’s the Mediterranean diet or the ketogenic diet. In order for people to adapt the diet, they need instruction and they need to be able to ask questions; those would be significant challenges when recommending the diets that restrict foods allowed, which could either be vegan, the very low fat, or the ketogenic diet.
The final consideration is the opportunities presented to provide patients with good information about the diet. The problem as I see it is that physicians, physician assistants, and nurse practitioners are not familiar enough with nutrition to be able to do that effectively in a medical practice, especially considering the time constraints for most healthcare practitioners. The obvious choice is to refer it to a dietetics department, but that type of consultation is not very often available in most medical practices and especially under most health insurance programs. I think the challenges are going to take years to overcome.
My thoughts on these guidelines are as follows. I thought the researchers did a credible job in coming up with their recommendations. They analyzed popular diets objectively and assessed them based on the AHA Dietary Guidance. But there is nothing new here.
Since 1974, more fruits and vegetables and a reduction on fat intake have been recommended as the foundation of every diet. No matter how many diets have come and gone, no matter how many are yet to be developed, we have not achieved the simplest and yet most obvious objectives. Food manufacturers certainly have had a role to play in this with low-fat and ultra-processed convenience food, but the choice is always with us.
The Bottom Line - As the lead author suggested in an interview, there were four recommendations across all popular diets: eat whole foods, eat more non-starchy vegetables, eat less added sugar, and eat less refined grains. If we could start with that, I think our hearts would love us for it.
