For years, we have been told that dietary cholesterol is bad, being the primary culprit of our largest cause of mortality – heart disease. This so-called “fact” has become so ingrained in our thinking that when researchers finally brought the truth to light and declared dietary cholesterol is NOT the problem, we turned a deaf ear.
Few consumers realized that when the U.S. Department of Health and Human Services rolled out the latest edition of their 2015-2020 Dietary Guidelines for Americans, something was missing – the former limits on dietary cholesterol. The new guidelines state,
“The Key Recommendation from the 2010 Dietary Guidelines to limit consumption of dietary cholesterol to 300 mg per day is not included in the 2015 edition… More research is needed regarding the dose-response relationship between dietary cholesterol and blood cholesterol levels. Adequate evidence is not available for a quantitative limit for dietary cholesterol specific to the Dietary Guidelines.”
Now I’m certainly not a fan of the USDA dietary guidelines, but this was a humbling move for them and one that deserves recognition. While most of the USDA dietary guidelines are heavily influenced by lobbyists and monetary gain, this new directive was actually based on science – or rather – the lack thereof.
The sad reality is that “old habits die hard” and most Americans are still seeped in the thinking that they must limit their cholesterol intake. This unfortunate belief leads to a different set of health problems that are linked to inadequate cholesterol intake.
Saturated fats and dietary cholesterol do, indeed, increase LDL cholesterol in the blood, but as research continues to progress in this area, new studies are emerging to show that the food items traditionally used to replace cholesterol (namely, carbohydrates) may have a worse impact on heart health. A diet rich in refined carbohydrates (aka. grains and sugars) can increase “bad” LDL cholesterol in the blood must faster than dietary cholesterol.
The real confusion lies in the fact that there are two different forms of LDL cholesterol – a larger (naturally occurring) LDL cholesterol and a smaller, oxidized LDL cholesterol. The larger form is not dangerous and does not increase your risk for heart disease. The smaller LDL cholesterol is dangerous and does increase your risk for heart disease. And unfortunately, the traditional lab tests do not distinguish between these two forms. If your LDL cholesterol is high, one must only look at their dietary habits to make an educated guess regarding whether that number is dangerous or not.
Dietary cholesterol (found in animal products, dairy and eggs) may increase the larger LDL cholesterol, but that is the safer form. On the other hand, refined carbohydrates (from refined flours and sugars) increases the smaller, dangerous LDL cholesterol and can most certainly be a risk factor for heart disease.
Sugar and carbohydrate intake has been steadily increasing over the past several decades and one of the most influential movements to spawn this growth was the fat free diet craze of the 1980s and 1990s. When fat was removed from common foodstuffs, the old recipes had to be revamped to retain the flavor and texture that fat provided. Therefore, sugar and salt was added in place of fat, and America’s sugar intake took another dive upward. As studies continue to point to the negative effects of sugar and carbohydrates on heart health, it may be prudent to ask the question of why federal dietary guidelines still refuse to acknowledge this connection and in fact, why efforts for more advanced studies have been stifled. To the keen observer, this actually is not a conundrum. After all, grains and sugar are commodity foodstuffs heavily subsidized by the government, so who would fund studies that would link these foodstuffs to America’s top cause of mortality?
It is high time that we stop demonizing eggs and natural sources of dietary cholesterol, and begin targeting some of the commodity crops for the mortality rates from poor heart health in this country. While we can be thankful that the U.S. Department of Health and Human Services has finally taken the long overdue step of acknowledging that cholesterol and eggs are not a health trap, and changing dietary guidelines accordingly, it will still take years to change America’s perception of these foods. Regardless, small steps lead to big leaps, so let’s give cheers for one step in the right direction.
References
U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition. December 2015. Available at http://health.gov/dietaryguidelines/2015/guidelines/.
Vafeiadou, K. (2015). Replacement of saturated with unsaturated fats had no impact on vascular function but beneficial effects on lipid biomarkers, E-selectin, and blood pressure: results from the randomized, controlled Dietary Intervention and VAScular function (DIVAS) study. American Journal of Clinical Nutrition, 102(1):40-8. doi: 10.3945/ajcn.114.097089.
Siri-Tarino et al. (2015). Saturated fats versus polyunsaturated fats versus carbohydrates for cardiovascular disease prevention and treatment. Annual Review of Nutrition, 35, 517–543. http://doi.org/10.1146/annurev-nutr-071714-034449
Odegaard et al. (2016). Oxidative stress, inflammation, endothelial dysfunction and incidence of type 2 diabetes. Cardiovascular Diabetology, 15, 51. http://doi.org/10.1186/s12933-016-0369-6
Virtanen et al. (2016). Associations of egg and cholesterol intakes with carotid intima-media thickness and risk of incident coronary artery disease according to apolipoprotein E phenotype in men: the Kuopio Ischaemic Heart Disease Risk Factor Study. American Journal of Clinical Nutrition, 103(3): 95-901. doi: 10.3945/ajcn.115.122317.
Te Morenga et al. (2014). Dietary sugars and cardiometabolic risk: systematic review and meta-analyses of randomized controlled trials of the effects on blood pressure and lipids. American Journal of Clinical Nutrition, 100(1): 65-79. doi: 10.3945/ajcn.113.081521.