Cardiovascular Disease
Cardiovascular disease, otherwise commonly called heart disease and stroke, are the largest single cause of mortality.
According to the World Health Organization and Center For Disease Control and Prevention, of the 56.9 million deaths globally in 2016, 15.2 million (26%) were due to heart disease and stroke. In contrast, a mere 1.4 million (2.4%) were due to road injuries[1] [2] [3]. Nearly every year, cardiovascular diseases are the number one cause of death. Over the years there have been many proposed mechanisms and likely candidates for causation. One of the most studied is cholesterol, and due both to that and the contentious nature of cholesterol on online health circles (particularly alt-med and health trends) it is the main focus of this article.
Contents
Relevance to Veganism
Vegetarians and vegans are consistently found to have lower risk for cardiovascular disease, and this makes up a large part of the health argument against meat. It makes a strong argument for at least reduction of most animal product consumption and incorporating more healthy plant-based foods, though as discussed elsewhere the health argument doesn't strictly recommend veganism, since very small amounts of animal products are probably not significant and it's hard to make any compelling case for health against leather, fur, or animal tested cosmetics which vegans typically avoid. Regardless of the degree of reduction it compels, any reduction in animal products is a reduction in animal suffering too which is an important goal of veganism (not just making people vegan). There are concerns for unintended consequences that have to be kept in mind, see health argument and one step for more.
Causes
Saturated Fat
Over the years there have been many proposed mechanisms and likely candidates for causation. With death and cardiovascular disease on the rise in the 1950s, research was undertaken to determine the best course of preventive action. Work on rabbits and other mammals found that feeding certain lipids induced atherosclerosis. Correlations in population (epidemiology) research showed a correlation with total fat and rates of heart disease. Later this research was criticized by researchers Yerushalmy and Hilaboe. They found that animal protein showed an even stronger association casting doubt on whether fat was really to blame. However, this makes sense given this was before it was known that saturated fat was uniquely damaging to heart health, and so animal protein would show a stronger association than total fat. In the following years a scientific consensus has formed to keep saturated fat below 5-10% of total calories for the prevention of cardiovascular disease. For a full article on why this is, and an exploration of arguments skeptics use, see the full article on Saturated Fatty Acids
Cholesterol
The main mechanism by which saturated fatty acids raise heart disease risk, is by increasing cholesterol; a fatty molecule in the blood strongly linked to increased plaque formation. The more of it one has, the higher their risk of the disease. Some of the most transformative work in this regard came from Mike Brown and Joe Goldstein, who had been performing various experiments on cholesterol metabolism. Brown and Goldstein found that those with a genetic condition characterized by elevated LDL-cholesterol (familial hypercholesterolemia) had LDL that would not bind to the rate-controlling enzyme of cholesterol synthesis known as, HMG-CoA reductase [1]. HMG-CoA reductase is the main target of the class of cholesterol controlling statin medication used today. Ultimately, their work lead to the discovery of the LDL receptor, earning them the Nobel Prize in Physiology and Medicine in 1985 (A. G. Motulsky,. 1986). Brown and Goldstein paved the way and were paramount in understanding cholesterol in the later years. Today, and thirteen Nobel Prizes later, there is a near-unanimous scientific agreement on the role of cholesterol in heart disease [2]. There is high-quality evidence that demonstrates this, and medications such as statins and PCSK9 inhibitors have been created with the intent of saving lives and preventing the disease. For the reasons why this is, see the full article on Cholesterol
