Eggs are awesome, taste great in a variety of recipes, are cheap, easy to cook and are one of the richest food sources of wholesome nutrition. Some of us even compromise our strict vegetarian beliefs and become an eggetarian. Being a rich (and extremely cheap) source of good quality protein as well as vitamins and minerals, eggs have existed as one of the staples in traditional healthy recipes all around the world.
However, the yolk (yellow) part of the eggs contain cholesterol and since our generation is the age of obesity and heart issues, dietitians advise us from staying away from the yolk part and just ingest the egg whites. These recommendations are based on very old dietary guidelines and somehow have prevailed even now. But does consumption of full eggs (yolks included) really bad for health? Let’s delve into what scientific studies show us:
Cholesterol is present in all animal cells and is vital for your body. It is involved in the synthesis of vitamin D, bile acids and essential hormones(including sex hormones). Your body makes it on a daily basis and adjusts its production according to the amount you absorb from your dietary cholesterol (what you eat) which is controlled by multiple feedback loops that ensure that its concentration is maintained within a very narrow range. Cholesterol is also of different types and not all cholesterol particles are bad. e.g. the good guys (like HDL) and the bad guys (like VLDL). Some are carriers, some get deposited and it’s get really complicated. All complexity aside, all you need to know is your total cholesterol count means nothing and the ratios between the good and bad particles matter more.
Cholesterol Intake and Heart Health
Without muddling much into the history of how dietitians concurred cholesterol was bad for health, lets just get into the research. This Research Review published in British Journal of Nutrition in 2011 is a great place to start understanding this topic in depth. It concludes that ingesting cholesterol doesn’t significantly affect plasma cholesterol levels (cholesterol in blood) and that there is no link between dietary cholesterol and cardiovascular diseases. Here’s another review showing that dietary cholesterol is not associated with coronary heart diseases or lower mortality. It also states that increase in the LDL:HDL ratio (which matters) change per 100 mg/day change in dietary cholesterol is from 2.60 to 2.61 only (very low). Both of these research reviews reference to research studies which focused on eggs consumption.
What about Eggs in Particular?
Here’s a meta-analysis (including 16 studies) which states that egg consumption is not associated with higher heart disease risk and cardiac mortality in healthy population. Need more proof? This is another research review which summarizes that restricting egg consumption in healthy individuals is baseless and inclusion of eggs provide multiple health benefits for normal healthy adults. You may find one or two biased studies which show otherwise and this is why we always back up our articles with research reviews and meta-analyses which look at multiple studies and adjust for flaws in study designs.
Also, you typical dietitian may say one or two egg yolks per week is beneficial and anything over it is bad. Here’s a research study which shows that egg consumption (2 eggs per day) doesn’t adversely affect endothenial function (of inner lining of blood vessels). By the way, endothenial function is a very good indicator of heart related risks.
What about Unhealthy People?
Focusing on heart diseases and type 2 diabetes, this systematic review concluded that dietary interventions that including eggs may reduce the risk of Type 2 diabetes and metabolic syndrome (obesity, low metabolism, heart diseases) in healthy people. It also said that there is evidence lacking for diabetes patients to limit their eggs intake as most studies which found adverse effects of eggs in patients lacked adjustment for dietary confounders.
In fact, In diabetic patients too, if taken as part of a calorie restricted high protein diet, egg consumption improves blood lipid profile and plasma glucose levels as shown in this study published in 2011. Even a high intake like 3 eggs per day in overweight men increased their HDL levels (good cholesterol) and decreased markers of risk factors for heart diseases, if maintained in a carbohydrate restricted diet like in this study.
There is very interesting research going on while trying to study health benefits of egg consumption in low carbohydrate diets. This study credits lutein, an antioxidant found in eggs to cause lowered inflammatory response in overweight men on a carb restricted diet. On the other hand, this one concludes that since egg Consumption promotes formation of larger LDL and HDL, this is leading to an increase in plasma lutein and zeaxanthin both of which have multiple benefits for heart health.
The myths of not eating egg yolks must go, at least for normal population. While Indian dietitians still confidently preach the cholesterol myth, they often forget that yolks are the most nutritious part of the egg because all the fat soluble vitamins reside in the yolks and not in the whites. Look at this figure on the right and judge for yourself. Besides, egg whites are pale and boring while yolks are colorful and tasty and this may play a critical part in developing a habit of eating healthy for someone who’s just starting to nudge away from junk food. Remember, habits shape health.
In Lucem Scientiam