Diet and Heart Health – The Dawn of a New Era

Diet and Heart Health - The beginning of a New Era?The 2015 Dietary Guidelines for Americans are due to be published later this year. The Scientific Report of the 2015 Dietary Guidelines Advisory Committee (DGAC) released February 23 this year suggested that we may see important changes of direction in certain areas.

Since the publication of the 2010 Dietary Guidelines important scientific data has emerged suggesting that the role of sodium intake, different types of dietary fats, carbohydrates, and added sugars may have to be reevaluated.

In general, dietary guidelines encourage people to focus on eating a healthful diet. Such a diet focuses on foods and beverages that guarantee adequate nutrition, achieve and maintain a healthy weight, promote health, and prevent disease.

Recently, the Academy of Nutrition and Dietetics published their commentary on the Scientific Report of the 2015 DGAC. The Academy is the largest association of food and nutrition professionals in the United States.

Interestingly, the Academy suggests a major revision of key issues that are likely to affect our view on the relationship between diet and heart health.

Diet and Heart Health

Initially, the dietary guidelines were born in an era where the mortality from coronary heart disease (CHD) was rising at a very rapid rate. At the beginning of the 20th century, acute heart attack (myocardial infarction) was relatively unknown. Fifty years later it was recognized as the most common cause of death in developed countries.

Public authorities were helpless. Here was a disease that brought an end to the lives of many people in their prime. It tragically, without warning, robbed wives of their husbands, husbands of their wives, and children of their parents. Something had to be done.

It soon became apparent that the risk of CHD was correlated with blood levels of cholesterol. Therefore, not surprisingly, blood cholesterol became a target in the fight against CHD.

Ever since the beginning of the 1960s, “eat less fat, in particular, less saturated fat, and cholesterol” has been the message from public health authorities and medical professionals. Food manufacturers have played along by emphasizing low-fat food varieties and highlighting “low-fat” as an important trademark

For the last 30 years, we have seen a dramatic fall in mortality from CHD and age-adjusted incidence has dropped as well. This is due to many factors, one of them likely being the lowering of blood cholesterol in the population.

However, the burden of CHD is still very high, partly due to the aging of the population. Furthermore, we have seen a rapid rise in obesity and related disorders such as type 2 diabetes, obstructive sleep apnea, non-alcoholic fatty liver disease, atrial fibrillation and some types of cancer.

The Academy’s Comments

Several issues addressed in the recent Academy of Nutrition and Dietetics’ commentary to the DAGC are of particular interest. These deal with salt intake, red meat, dietary cholesterol, saturated fats and added sugar.

Sodium

The Academy highlights the fact that there is “a distinct and growing lack of scientific consensus on making a single sodium consumption recommendation for all Americans, owing to a growing body of research suggesting that the low sodium levels recommended by the DGAC are actually associated with increased mortality for healthy individuals“.

There are several studies that have suggested that diets restricted in sodium may be beneficial for individuals with high blood pressure. However, the Academy is concerned that the recent DGAC’s scientific report appears to use conclusions from these studies as “a basis for making a general recommendation that all American adults consume less than 2,300 mg/day of sodium.”

The DGAC appears to recognize that it may be difficult to identify those who may benefit from restricting dietary salt and sodium. Therefore, in light of the growing evidence that sodium restriction at the level recommended may cause harm, adopting such a recommendation to the general population appears controversial.

Red Meat

The DGAC recommends that the US population should be encouraged and guided to consume dietary patterns that are rich in vegetables, fruits, whole grains, seafood, legumes, and nuts; moderate in low-fat dairy products and alcohol; lower in red and processed meat; and low in sugar-sweetened foods and beverages and refined grains.

The Academy does not “interpret that recommendation as impugning the healthfulness of red meat or its place in recommended meal patterns…

The Academy points out that approximately 80 percent of Americans meet the intake recommendation for animal proteins, mainly based on the consumption of meat, poultry and eggs. However, “data from NHANES for the consumption of red meat alone suggests that American adults on average eat almost as much red meat per week (20 oz) as the USDA recommends for meat, poultry, and eggs combined (26 oz)“.

The Academy seems to agree “(a) that red meat consumption exceeds recommendation for most subgroups and (b) that a greater share of recommended protein consumption should be met by seafood, legumes, and nuts.”

Dietary Cholesterol

The Academy “supports the decision by the 2015 DGAC not to carry forward previous recommendations that cholesterol intake be limited to no more than 300 mg/day, as available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol.”

The Academy also lauds the DGAC for its willingness to update positions based on new evidence. However, whether such an obvious act is praiseworthy or not is debatable.

The Academy writes; “It has been said that the unit of measurement for scientific progress is scientific error. Every new discovery proves old conclusions wrong, and every incorrect conclusion of the past marks new knowledge that has taken its place. The Committee’s willingness to update positions based on new evidence is laudable.”

Saturated Fat

In the spirit of the 2015 DGAC’s commendable revision of previous DGAC recommendations to limit dietary cholesterol, the Academy suggests that HHS and USDA support a similar revision deemphasizing saturated fat as a nutrient of concern. While the body of research linking saturated fat intake to the modulation of LDL and other circulating lipoprotein concentrations is significant, this evidence is essentially irrelevant to the question of the relationship between diet and risk for cardiovascular disease.”

The above conclusion suggests a major change of direction in how health authorities view the role of dietary fats in health and disease.

The Academy writes, “We commend the DGAC on a thorough and accurate review of the current best evidence with regard to the body of evidence relating dietary fats to cardiovascular disease outcomes. However, we are concerned that the evidence does not lead to the conclusion that saturated fats should be replaced with polyunsaturated fats for the greatest health benefit.”

The Academy arguments that “carbohydrate intake conveys a greater amount of cardiovascular disease risk than does saturated fat”.

It is concluded “that the substitution of polyunsaturated fat for carbohydrate will result in a lesser net risk for cardiovascular disease than if polyunsaturated fat were substituted for saturated fat. This is true because carbohydrate contributes a greater amount to the risk for cardiovascular disease than saturated fat, so the replacement of carbohydrate will necessarily result in a greater improvement in risk”.

“Therefore, it appears that the evidence summarized by the DGAC suggests that the most effective recommendation for the reduction in cardiovascular disease would be a reduction in carbohydrate intake with replacement by polyunsaturated fat.”

Furthermore:

This simplified recommendation would also aid in creating a consistent overall message of the DGA, allowing for consumer messaging to focus on benefits of decreasing added sugars in the diet to reduce cardiovascular disease, obesity, and type 2 diabetes, consistent with the conclusion statements in the added sugars section of the Scientific Report.

Added Sugar

The Academy’s view on added sugar is very clear;

Of all the crosscutting topics reviewed, the evidence is strongest that a reduction in the intake of added sugars will improve the health of the American public. The identification and recognition of the specific health risks posed by added sugars represents an important step forward for public health. We recommend that these risks and recommendations be featured prominently in the 2015 Dietary Guidelines for Americans.

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David_Brown
David_Brown
5 years ago

“Therefore, it appears that the evidence summarized by the DGAC suggests that the most effective recommendation for the reduction in cardiovascular disease would be a reduction in carbohydrate intake with replacement by polyunsaturated fat.” The Academy is so close to getting it right! But they’re still ignoring linoleic acid research. https://www.bmj.com/content/349/bmj.g7255/rapid-responses Quite likely, the reason linoleic acid is considered heart protective is because of a 2014 Meta-Analysis. From the Abstract: “Comparing the highest to the lowest category dietary LA was associated with a 15% lower risk of CHD events and a 21% lower risk of CHD deaths. A 5% of… Read more »

tannngl
tannngl
5 years ago

Thank you for this report!

And the awesome ship of state, I mean health guidance, begins its slow 180…

You know, nothing is ever as simple as any disease brought about by one cause. Saturated fat as the culprit in CHD was a terrible (I think murderous) recommendation to entire nations. How many deaths and diseases has this brought about?
Every disease is more complex than anyone understands because we don’t fully understand physiology. Humility and objectivity would be nice in scientific research along with actual use of the actual scientific method.

Katy Powers
Katy Powers
5 years ago

Thanks for the article!

bob_johnston
bob_johnston
5 years ago

It is concluded “that the substitution of polyunsaturated fat for carbohydrate will result in a lesser net risk for cardiovascular disease than if polyunsaturated fat were substituted for saturated fat. This is true because carbohydrate contributes a greater amount to the risk for cardiovascular disease than saturated fat, so the replacement of carbohydrate will necessarily result in a greater improvement in risk”. “Therefore, it appears that the evidence summarized by the DGAC suggests that the most effective recommendation for the reduction in cardiovascular disease would be a reduction in carbohydrate intake with replacement by polyunsaturated fat.” Good lord, this is… Read more »

Mie
Mie
5 years ago
Reply to  bob_johnston

Funny you should mention poor reasoning, Bob. 🙂 1) There’s no such thing as “absolute health” in nutrition, it’s always a matter of relations and difference compared to something else, depending on your diet’s role in prevention of major diseases such as CHD, DM2 etc. etc. 2) The cigarette example is just plain ol’ BS because a) no amount of cigarettes is healthier than none at all whereas b) certain amount of PUFA is healthier than none at all. 3) “Say you” … err, stopped making stupid comments concerning replacements. Instead, check e.g. this out https://www.ncbi.nlm.nih.gov/pubmed/9006469 Or e.g. this https://ajcn.nutrition.org/content/89/5/1425.full… Read more »

bob_johnston
bob_johnston
5 years ago
Reply to  Mie

Mie – just stop. When all you have is simply nipicking analogies you really have no argument or anything relevant to say.

And your studies only are worthwhile if you believe that higher cholesterol is detrimental to health. I do not suffer from that misconception.

And now I’m done with you. I made the mistake of answering you on a prior post and that was a mistake I won’t make again.

Too-da-loo

Mie
Mie
5 years ago
Reply to  bob_johnston

Nope, the condition you have is called “denialism”.

And yes, yes, YES! Hopefully you will truly be done with me – meaning that you’ll stop spreading nonsense.

michael goroncy
michael goroncy
5 years ago

When this “2015 Dietary Guidelines
Advisory Committee “ report is published, I would begin at the end
‘Disclosure’ to ascertain if there is a whiff of vested interests
(Agricultural, Pharmaceutical or any other)….otherwise it is of no
use.

Erik Arnesen
Erik Arnesen
5 years ago

Regarding the statement that carbs increase risk more than PUFA lower risk, the Academy cites Jakobsen et al (2009), which I consider a good meta-analysis. However, they report that exchanging PUFA for SFA reduced risk for CHD events by 13 % and CHD deaths by 26 % per 5 % of energy intake, while exchanging carbs for SFA increased risk by 7 %. So it seems that substituting SFA with PUFA makes a bigger difference. And the Academy seem to ignore other findings that the increased risk is confined to refined/high glycemic carbs. That’s probably why most cohort studies about… Read more »

Mie
Mie
5 years ago
Reply to  Erik Arnesen

Precisely: the claim that carbs as such create a large risk than SAFA is … well, more like a brain fart than actual scientific criticism. Where’s the discussion of carb quality? SAFA carrier foods? In addition, the Academy has problems with this part: “The 2010 Institute of Medicine (IOM) report on the use of biomarkers as surrogates for disease outcomes examined LDL and HDL as case studies and concluded unequivocally that they were not suitable for use as surrogates for the impact of diet on heart disease.38 The IOM concluded that, “lowering LDL-C does not always correlate with improved patient… Read more »

Solomon Asare
Solomon Asare
5 years ago

Explaining this gradual shift is going to be difficult for a lot of practitioners. “It was apparent, clearly correlated, gave us significant reductions in mortality, but, eh not that we were wrong but…..”

Emaho
Emaho
5 years ago

My Mie, I’m a afraid you are lost in the weeds. How were our ancestors from over 10,000 years ago able to find a healthy diet without all of those nutritional studies? How did they know to eat the essential fatty acids? In fact, how were they able to eat the correct balance of essential polyunsaturated fatty acids? I would recommend the work of Dr. Weston A Price as he respected our ancestors’ ability to see healthy food in all of the weeds: https://www.westonaprice.org Also, Mark Sisson has a similar respect: https://www.marksdailyapple.com Lastly, if you wish to find out how… Read more »

Mie
Mie
5 years ago
Reply to  Emaho

The answer to your first question: they just ate what was available and of some benefit (e.g. cooked meat better than raw meat in many ways) at that time. Don’t confuse “available” with “optimal”. I agree, however, with you on paleo diet being a healthy option to what most of us consume on a daily basis. As for your recommendations: thanks, but I prefer scientific studies, not popular literature with an agenda. Besides, your list didn’t really offer anything new. I’ve read Taubes and his critics, and e.g. Seth here https://thescienceofnutrition.wordpress.com/ shows very clearly & thoroughly just what’s wrong with… Read more »

Jeffrey Brown
Jeffrey Brown
5 years ago

Dr. Sigurdsson

If a patient presented with the following, would you be inclined to recommend statin therapy?

Female, age 55, non-smoker, normal BP, no known cardiac risk factors, normal fasting glucose levels.

Total Cholesterol: 350
Triglycerides (TG): 104
HDL: 100
LDL: 229
Cholesterol/HDL: 3.5
TG/HDL: 1.03

Peak LDL particle size very large, at 231.1 Angstroms, but high total LDL particle number, 1550.
High ApoB, 147.
Very low HS CRP, 0.2 (no indication of inflammation).

Axel F Sigurdsson
Axel F Sigurdsson
5 years ago
Reply to  Jeffrey Brown

Jeffrey
I would probably not recommend statin treatment. The risk of cardiovascular events for such an individual appears quite low and in my opinion too low to risk statin treatment. Therefore, unless there are other factors suggesting higher risk (such as family history of premature coronary heart disease), my answer to your question is no.

Jeffrey Brown
Jeffrey Brown
5 years ago

Dr. Sigurdsson, Thank you very much for your prompt reply. As layperson, after reviewing the available research on risk versus benefits for middle aged women, with no known risk factors (and with a sky high HDL number), I had reached the same conclusion. As you would no doubt expect, the patient’s internist is strongly advocating statin treatment. One of the most surprising things have I read lately is that US doctors are being evaluated by insurance companies partly based on their patients’ average LDL cholesterol numbers, which provides an obvious incentive for doctors to get their patients’ LDL numbers down.… Read more »

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