The Journal of the American Medical Association (JAMA) has a commentary in the August 11 edition entitled: "Dietary Guidelines in the 21st Century - a Time for Food" by Darius Mozaffarian, MD, DrPH and David S. Ludwig, MD, PhD.
The purpose of this post is to summarize and review the article and to talk about whether it is consistent with the e4e dietary recommendations. Special thanks to
Ashley at
itsofinterest.com for providing me with a copy of the article.
Commentary Overview
The second part of the title is a great start. A time for food. The article itself is in three parts, I will summarize the parts below.
Section 1 - Introduction
In the introduction in the commentary, they talk about how the last 200 years have been characterized by the discovery of finer and finer detail of the nutrients and nutrient deficiencies that led to widespread disease. This has led to a reductionist perspective in our food choices.
Section 2 - Dietary Guidelines in the Age of Chronic Disease
This reductionist view led to guidelines in the 70s and 80s around minimum and maximum intakes of nutrients. Although appealing, the RDAs have not worked, perhaps simply because of the complexity involved in translating these recommendations into real dietary choices.
I will copy the last paragraph of this section directly with some highlights of my own. It is an amazing admission.
"Nutritional science has advanced rapidly, and the evi-
dence now demonstrates the major limitations of nutrient-
based metrics for prevention of chronic disease.
The propor-
tion of total energy from fat appears largely unrelated to risk
of cardiovascular disease, cancer, diabetes, or obesity. Satu-
rated fat—targeted by nearly all nutrition-related profes-
sional organizations and governmental agencies—has little re-
lation to heart disease within most prevailing dietary patterns.
Typical recommendations to consume at least half of total
energy as carbohydrate, a
nutrient for which humans have no
absolute requirement, conflate foods with widely divergent
physiologic effects (eg, brown rice, white bread, apples). Foods
are grouped based on protein content (chicken, fish, beans,
nuts) despite demonstrably different health effects. With
few
exceptions (eg, omega-3 fats, trans fat, salt),
individual com-
pounds in isolation have small effects on chronic diseases.8
Thus,
little of the information found on food labels’ “nutri-
tion facts” panels
provides useful guidance for selecting
healthier foods to prevent chronic disease."
All I can say is WOW.
To sum up:
Fat ingestion, in general, is fine.
Saturated Fat is not bad.
Carbohydrate food sources are not necessary and are not created equal.
Protein food sources are not created equal.
Individual compounds in isolation are largely unimportant.
Food labels suck.
The only thing that I wildly disagree with in this paragraph is that they included salt as a compound as an exception to the compounds in isolation comment. Salt is nowhere close to the villain that people make it out to be.
Section 3 - The Need for a New Approach
This is the longest section, and I would have broken it into at least two parts, but I digress.
They start this section by citing associations between food classes and disease from a paper called "Dietary Patterns and risk of mortality from cardiovascular disease, cancer, and all causes in a prospective cohort of women", by Heideman, Schulze, Franco, et al.
They go on to say that the effects of foods "likely reflect complex, synergistic contributions from
and interactions among food structure, preparation methods, fatty acid profile, carbohydrate quality (e.g, glycemic index, fiber content), protein type, micronutrients, and phytochemicals."
So far so good.
Then they say that "Healthy eating patterns share many characteristics, emphasizing whole or minimally processed foods and vegetable oils, with few highly processed foods or sugary beverages. Such diets are also naturally lower in salt, trans fat, saturated fat, refined carbohydrates, and added sugars; are higher in unsaturated fats, fiber, antioxidants, minerals, and phytochemicals; and are more satiating."
This is mostly ok, but they are somewhat contradicting their earlier statement that saturated fat is ok. They're still missing the boat on salt, and unsaturated fats are a mixed bag. Unsaturated fat is not by itself good or bad. The devil is in the details.
They continue by saying that the nutrient based approach to diet has fostered products that replace fat with refined carbohydrate, "providing an aura of healthiness but without
actual health benefits." A national obesity prevention program categorizes whole-milk yogurt and cheese with french fries and donuts as foods together (eat only occasionally). Puts sauteed vegetables and canned tuna in the same category as pretzels and processed cheese spread (eat sometimes). Puts trimmed beef and vegetables and fat free mayonnaise as foods to eat almost anytime. They fortify processed food parts with vitamins and call them healthy.
Recently, there has been movement towards recommending food rather than simply nutrients. Nutrients are still important, we should not simply throw away the last several decades. Although this is a promising direction, they believe that much research work still remains to be done.
They finish with the following:
"The relatively recent focus on nutrients parallels an increas-
ing discrepancy between theory and practice: the greater the
focus on nutrients, the less healthful foods have become. As
national and international organizations update dietary guide-
lines,
nutrient targets should largely be replaced by food-based
targets. Such change would facilitate translation to the pub-
lic, correspond with scientific advances in chronic disease pre-
vention, mitigate industry manipulation, and remedy wide-
spread misperceptions about what constitutes healthful diets.
"Although this approach may seem radical, it actually rep-
resents a
return to more traditional, time-tested ways of eat-
ing. Healthier food-based dietary patterns have existed for
generations among some populations. Modern nutritional
science now provides substantial evidence for how foods and
food-based patterns affect health, guiding the design of more
effective approaches for the prevention of chronic disease."
e4e Take On This
Wow. This is great. It is generally consistent with the e4e recommendations in,
"Eat Food, Light on Carbs, Mindfully." I talk about some general targets for macronutrients, depending on goals, but interestingly once you go light on carbs and stick to the fringes of your grocery store (food), it's hard to go too far wrong.
Regarding my comments on salt, please read the article
"The (Political) Science of Salt" by Gary Taubes.
The 2010 food pyramid looks like it will be more of the same old stuff. This commentary represents a significant step towards dietary sanity in a mainstream medical journal. Is sanity finally winning?