Benefits Of Weight Loss In Coronary Heart Disease

Overview

Cardiovascular disease, which can be defined as diseases of the heart and blood vessels in general, is by far the leading cause of death globally. Stroke and heart attack are the two most important pathologies in this group of maladies. In this article, we will take an in-depth look at coronary heart disease (or more accurately known as coronary artery disease), which also includes heart attack as an acute form, and look at the influence of some important lifestyle factors on it, specifically those of diet, physical activity and weight. 

Benefits of weight loss in coronary heart disease

Before looking at the benefits of weight loss in coronary heart disease, one should get a general idea about what coronary artery disease (CAD) is. Essentially like every other organ, the heart needs nourishment to function properly, and because the heart is an extremely specialized muscle that must be active 24/7, this nourishment is critically dependant upon a system of blood vessels that give the heart its oxygen and nutrients, which are called the coronary arteries. The chronic condition whereby the blood supply to the heart is partially but chronically obstructed due to problems (especially narrowing and stiffening of the coronary arteries) is called coronary artery disease or coronary heart disease. This may lead to a state where whenever there is an increased demand like any form of physical activity, the heart is unable to keep up with it anymore and severe chest pain and breathlessness ensue, which later might improve with rest. This alarming symptom is called angina.

The obstruction in the coronary arteries is the result of a process called atherosclerosis. This is when what is called an atheroma starts to build up inside the walls of the arteries. An atheroma begins with a small and innocuous precipitation of fat within the walls of the arteries. This leads to the narrowing of the arteries, causing obstruction,  and also causing disruption to blood flow. This disruption, coupled with the abnormal biological signals produced by the fatty lesion, can lead to the formation of blood clots, which can later on completely block the already narrowed coronary arteries, leading to heart attack. So a heart attack is essentially the acute and total blockage of one or more coronary arteries.

Atherosclerosis is a dynamic process. The initial precipitation of fat in our arteries is an inevitable process that happens in every single person by their teens without exception (this first buildup is called a fatty streak). Although this precipitation cannot be prevented, the subsequent transformation of a fatty streak into an atheroma is a process that is largely dependent on our lifestyle. Our diet, physical activity, weight and the presence of a chronic inflammatory state in our bodies are key determinants which dictate how rapid and significantly atherosclerosis proceeds from tiny fatty streaks into full-blown atheromas. As we can thus see, one of the most important things one can do for their health is to halt atherosclerosis through combating the mentioned variables, which also includes weight loss. 

American Heart Association studies indicate the presence of excess fat, especially hidden or visceral fat, acts as an independent risk factor for developing conditions related to heart and blood vessels and this is related to adverse outcomes in people with cardiovascular disease. This can, however, be minimized by lifestyle changes and weight management.”¹ According to the  British Heart Foundation obesity or being overweight predisposes to an increased risk of some other conditions like having a heart attack, stroke or even dementia caused by blockages in the blood vessels. Additionally, a major study of 5145 overweight patients published in the prestigious Lancet journal has also significantly demonstrated that patients who had lost at least 10% of their body weight had an overall 20% reduction in cardiovascular risk.³ So this theoretical framework is also supported by rigorous testing, proper evidence and data and is also endorsed by the most important cardiology associations in the world.

How does weight affect coronary heart disease?

This is a very complex topic, but in the most simple terms, the progression of fatty streaks in the arteries into full-blown atherosclerosis and the resultant atheromas is dependent on how much inflammation is going on in the fatty streak itself. As a general rule of thumb, saturated fat (which is found in higher amounts in animal fat) is more prone to inflammation than unsaturated fat (which is more abundant in plant fat). Additionally, chronic high blood pressure and the presence of diabetes (especially type 2 diabetes) also speed up the inflammation of fat in the walls of the arteries. 

Many of you have most likely heard of HDL and LDL cholesterol. HDL is usually considered to be good cholesterol and LDL bad cholesterol. While the reality in a biochemical sense is much more complicated (both HDL and LDL cholesterol are essential in the functioning of fat metabolism in the body), as a simple measure of health this simplification holds true. A type of cholesterol called VLDL is responsible for transporting essential fats from the liver (where they are processed) into the tissues of the body. While VLDL travels through the blood, it eventually turns into LDL which is responsible for delivering cholesterol into cells (cells use cholesterol to maintain membranes and produce hormones). Any remaining cholesterol is taken up by HDL and transported back to the liver for processing. Essentially, LDL brings cholesterol into cells while HDL clears cells of excess cholesterol. Two things to note here are that fat cells use a lot of cholesterol and that cholesterol is a type of molecule that is prone to oxidation and thus, inflammation. So bringing these two together, we can surmise that people who have a lot of fat cells use a lot of cholesterol, and this cholesterol speeds up fatty inflammation. LDL and HDL cholesterol could be thought of as measuring benchmarks of this balance. 

Weight loss ends up resulting in less cholesterol being used in fat cells and, therefore less oxidation, which will slow down atherosclerosis, thereby reducing the risk of heart disease and protecting heart health. Coronary heart disease is not the only type of cardiovascular disease that is protected against, but conditions like high blood pressure, congestive heart failure and other cardiovascular events like stroke also benefit from having a normal weight, preventing obesity and staying in a normal body mass index. 

How can I safely lose weight with coronary heart disease?

Weight change can be quite difficult, especially in people with established cardiovascular disease. Patients living with heart disease usually take several medications and some of these medications (such as beta blockers) can lead to weight gain and obesity. This, combined with physical inactivity resulting from the fact that activity can be associated with discomfort in cardiac patients, can lead to a spiral where maintaining a normal weight can be a tough goal. There are ways to combat excess body weight that can be utilized. Both the American Heart Association and the British Heart Foundation have many resources that can help with safe and effective weight loss for cardiac patients. These include dietary measures and physical activity to mitigate overall cardiovascular risk factors, increase cardiorespiratory fitness and help with secondary prevention for patients who have already experienced a cardiovascular event and require cardiac rehabilitation to go back to their normal lives. 

Summary

Maintaining healthy body weight is of critical importance for cardiac health. This should ideally be achieved through a combination of diet and physical activity, and there are many avenues through which one can tackle this daunting task.