Global Courant
Cardiovascular diseases are the number one cause of death in the Western world and affect people more and more as they get older. Because it’s our number one killer, it gets a lot of attention in the media and from our health services. The generally accepted wisdom is that we should all quit smoking, drink less and avoid saturated fat. Meanwhile, those with established cardiovascular disease and those thought to be at risk for future cardiovascular disease are prescribed drugs to alter their blood cholesterol and blood pressure. While the advice to stop smoking and drink less is undoubtedly based on good evidence, the other cornerstones of contemporary cardiovascular disease prevention and treatment are more controversial.
What is Cardiovascular Disease?
Cardiovascular disease encompasses a number of different conditions and so there are a number of possible causes. The main cardiovascular conditions that can cause premature death are:
- Atherosclerosis, perhaps the best known, when arteries clog up. This narrows the arteries and creates conditions where the artery eventually becomes clogged. If the artery is a coronary artery, one of the arteries that supply oxygen to the muscles around the heart, a heart attack ensues. If the artery is a carotid artery that supplies oxygen to the brain, a major stroke occurs. Heart attacks have a fancy name, myocardial infarction. Actually, myo stands for muscle, cardio for heart and infarction for tissue destruction due to lack of oxygen. That pretty much sums up what happens when a coronary artery is blocked.
- Aneurysms, which are bulging blood vessels that form when the walls of the blood vessels become too weak to handle the local blood pressure. If an aneurysm bursts, bleeding occurs and the lack of blood and the oxygen it carries to vital organs such as the heart and brain can be fatal. In the UK, according to NHS sources, the incidence of death from ruptured aneurysms is about 4-5% of that for heart attacks and strokes related to atherosclerosis. About 9,500 a year versus 162,000 a year.
- Heart failure occurs when the muscle that makes the heart beat stops working. This is due to a previous heart attack in about 2 out of 3 cases. It can also be caused by valve failure in 4% of cases, very high blood pressure, also 4%, alcohol and viruses, again 4% of cases. The remaining 20% have unknown causes. Using figures from the US, I estimate that it kills between 40 and 50,000 people each year in the UK. In other words, it is more common than death from aneurysms, but less common than death from heart attacks and strokes due to clogged arteries.
- Arrhythmias are heartbeats that become irregular, extremely fast, or slow due to abnormal electrical activity in the heart. They are very common, but are normally not fatal until a serious event, such as a heart attack, has already occurred.
So what causes cardiovascular disease?
The conditions described above are clearly worth avoiding. The main changes that occur in the body to cause the above problems are narrowing of arteries, weakening of blood vessels and damage to the heart muscle. Narrowing of arteries due to atherosclerosis is the main factor in all of this, causing almost all heart attacks and about 85% of strokes (15% are caused by bleeding). What exactly are the causes of cardiovascular disease? Below I list the factors that are commonly known and those that have strong evidence to support them, and then examine them.
- Blood cholesterol levels, especially cholesterol that is carried in the blood by low-density lipoproteins
- High blood pressure, particularly by causing damage to the lining of blood vessels. In some salt-sensitive people, too much salt raises blood pressure.
- Dietary cholesterol absorption from foods such as eggs and shrimp.
- Intake of saturated fats from foods such as red meat and cheese.
- Intake of damaged fats such as artificial trans fats.
- Proportions and total intake of polyunsaturated fats.
- Blood sugar.
Cholesterol level in the blood are much more complex in their effects than most people realize. While low cholesterol levels are associated with a reduced incidence of heart attacks, they are also associated with a greater risk of death, with depression, cancer, stroke and atrial fibrillation. This should give us food for thought when considering the importance of lowering cholesterol levels in people with something other than established cardiovascular disease. For most of us, a level classified as borderline high, such as between 200-240 dL/L (5.1-6.2 mmol/L), would probably be an optimal level. There is some evidence that higher levels protect against many types of stroke, especially hemorrhagic stroke where bleeding from blood vessels causes death. The above should not be surprising when you consider the role of cholesterol in the body. It is an integral part of all our cell membranes and is a precursor to many of our hormones, including vitamin D, which is increasingly associated with a reduced risk of many serious diseases.
High bloodpressure is associated with an increased risk of cardiovascular disease. However, the risk of high blood pressure also depends on the quality of the blood vessels. Damage to blood vessels is normally repaired and if we consume the right diet, it is likely that our blood vessels will repair themselves more quickly.
Diet cholesterol was the first target of government advice. However, it turns out that cholesterol from foods like shrimp, liver, and eggs doesn’t raise cholesterol levels in most people, and even if they did, it might not be a big deal. In fact, these high cholesterol foods are among the healthiest in the diet and contain a high amount of important micronutrients such as vitamins A, D and E, as well as minerals such as iron (liver), iodine (shrimp), and antioxidants (eggs and shrimp) .
Saturated fat has been increasingly becoming the villain in government campaigns lately, but is it that bad? Saturated fat has been in our diet since we evolved into humans, you would think our bodies would have learned to deal with it by now, and in fact there is plenty of evidence to suggest so. A 2011 review of 21 intervention studies conducted over the past decade found no reduction in the risk of death from cardiovascular disease after interventions to reduce or replace saturated fat with carbohydrates or polyunsaturated fats. It is clear that typical foods containing saturated fat are no worse for us than foods containing carbohydrates or polyunsaturated fat.
Damaged fats have come under increasing scrutiny over the past two decades. They are fats that have been heated to very high temperatures during their manufacture (or during cooking). When heated above about 160C, the molecules from which they are formed change into shapes that the human body does not recognize. Foods such as margarines and most packaged goods containing vegetable fats contain these damaged fats. They are clearly linked to an increased risk of cardiovascular disease.
Proportions of polyunsaturated fats to various other types of fat have been investigated by numerous studies. Most show that polyunsaturated fats, when increased as a total portion of calories, reduce the risk of cardiovascular disease. Without boring you with the details, this is most likely due to the presence of omega 3 fats such as those found in oily fish. Omega 3 fats have a powerful effect on cardiovascular disease risk, outperforming statins in many studies.
Blood sugar receive a lot of attention in people with diabetes, but very little in people without the condition. In short, if you walk around with too high a blood sugar level, your risk of cardiovascular disease is greatly increased. It is very important to ensure that your diet does not lead to chronically elevated blood sugar levels. For many, this means reducing the so-called glycemic load of their diet. Basically, try to moderate your intake of sugary drinks, cakes, candies and puddings, as well as starchy foods that break down into sugars before being absorbed from your digestive tract. These include bread, rice and potatoes.
What does this mean for my diet and lifestyle?
A diet that reduces your risk of cardiovascular disease and the damage it causes from heart attacks and strokes would follow the general principles below:
- Reduce the amount of junk food you eat. This is a very general point, but junk food generally contains too much salt, sugar, additives and trans fats. All this makes cardiovascular disease more likely. Examples include food from takeaways, convenience foods from supermarkets, and carbonated soft drinks.
- Eat more fruits and especially vegetables. Again, this is a large food group, but many fruits and vegetables contain nutrients that help protect and repair your arteries from damage. Examples include tomatoes that provide a high dose of lycopene when cooked to suppress oxidative damage to blood vessels, cooked beetroot that can release substances that relax your blood vessels, and plants from the allium family, such as garlic, onions and leeks that prevent blood clotting and constriction. of arteries.
- Try to include some omega 3 fats in your diet. The most effective way to do this is through oily fish like mackerel, herring, trout, sardines, sardines, kippers and tuna (not the canned stuff). One problem with these fish is that they can accumulate high levels of toxic heavy metals and pesticides in their fatty tissues. This is why pregnant women are sometimes advised to moderate their intake. One way around this is to use fish oil that has been processed to remove these contaminants. For vegetarians, omega 3 can be obtained from seaweed extracts. Flaxseed oil can also be effective in people with the ability to convert the omega 3 fat into a more potent form.
- When it comes to cholesterol and saturated fats I wouldn’t worry too much. If they come from good sources, such as pasture-raised cows, organic free-range chickens, you will probably benefit more than harm. As mentioned above, the evidence linking cholesterol and saturated fat intake to heart disease is inconsistent and biased by the drug companies’ huge interest in funding studies that try to establish the link to justify their drug sales.
- I have not covered exercise in this article, but regular daily exercise is very effective in reducing the risk of cardiovascular disease. Each exercise will be helpful if it progressively builds on your current capabilities. For some, this may mean covering greater distances at increasingly higher speeds each day. Some resistance training is helpful for those who already have basic fitness. Caution is advised for those with existing cardiovascular disease, but it will be very beneficial as long as your body responds to the workout without a crisis event. In that case, consult a doctor or other professional who is personally involved in your care. For those who are already fit and wondering what’s best for their cardiovascular health, the general rule is to build fitness steadily and recover well from tough sessions. Normally what makes you fitter is also good for you, if training exhausts you, it is not good for your fitness or health.
Diet, exercise and cardiovascular disease
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