The general understanding of cholesterol and its link to heart disease was in accordance to what is described in most generic “health” sites – British Heart Foundation, WebMD, MayoClinic. High cholesterol in blood leads to its accumulation in the arteries (the main blood supply to our heart). Deposition of cholesterol in the arteries causes them to clog up, preventing blood from reaching the heart, a phenomenon also known as “atherosclerosis”. Historically, this has been considered the primary cause of heart disease.
In theory, high cholesterol leads to clogged arteries, a leading risk factor for heart disease. Is this the case in practice?
For years, experts have recommended diets designed to reduce cholesterol levels and pharmaceutical companies spent billions developing statins, cholesterol lowering medication. However, here at Skeptific we have reviewed the literature for you and found a number of studies that actually suggest the very opposite.
A study assessed 140,000 hospitalisations due to heart attacks and found that patients’ cholesterol levels were actually low at the time of hospitalisation. Another study looked at all the research papers published in Pubmed – the most widely used database for research papers – including the key words “LDL as a risk factor for health”. LDL is widely considered to be a type of “bad cholesterol”. They found that people with high LDL lived longer than people with low LDL, the number of patients in these papers summed up to a total of 68,000. Moreover, in a study with 4,525 participants it was shown that extremely low levels of cholesterol in the elderly (age 65-85) was a signal for rapidly declining health.
If we think of the regular functions of cholesterol, it would make complete sense that very low levels of cholesterol can be harmful for the body. Cholesterol is responsible for the production of sex hormones, bile acid and vitamin D. It also plays a key role in communication and transport of molecules, and metabolism. It is vital for our cells to be able to maintain their basic structure. Our bodies wouldn’t manufacture it if it was dispensable.
In theory, statins lower cholesterol therefore decrease heart disease and mortality. Is this the case in practice?
Statins are the most widely prescribed cholesterol lowering drugs, with approximately 1.5 million people aged above 75 taking statins in the UK alone. They interfere with the production of cholesterol, and thereby lower overall cholesterol levels in our body. However, this also has a number of side effects as lowering cholesterol would disrupt normal biological functions cholesterol is responsible for. Side effects of statins include: muscle ache, memory loss and dementia. Surprisingly, in 1 in 50 patients statins cause type 2 diabetes, a major cause of heart disease in itself! Despite this, statins are prescribed as a lifelong preventative medication. Are lifelong pharmaceutical interventions better than lifestyle changes? We are a little skeptical, to say the least.
A review of industry-sponsored randomised controlled trials (considered the most accurate form of experimental trial) showed that the life expectancy for patients taking statins for 2 years only increased by only 4 days. On the other hand, in the Lyon Diet Heart Study where patients adopted the Mediterranean diet as a method of prevention, this improved both heart attacks and all cause mortality, despite cholesterol levels remaining the same.
Just last year the American Heart Association report acknowledged lack of scientific basis for concerns regarding dietary cholesterol. General guidelines for doctors and patients struggle to keep up to date with constantly evolving scientific literature, but in this case there has been conflicting literature for so many years – it was impossible for policy makers not to address it.