For the last half century, high cholesterol has been thought of as the primary risk factor for coronary heart disease, and that a diet high in saturated fat and cholesterol causes a buildup of plaque and blocks blood vessels. This way of thinking has been widely accepted by many physicians and the general public alike, despite the overwhelming body of evidence that suggests otherwise.
Heart disease was relatively rare at the turn of the century, accounting for approximately 8% of all deaths in the United States. Today coronary heart disease, or CHD, accounts for about 45% of all deaths. Furthermore, the incidence of heart disease rose steeply between 1920 and 1960.
Given the sharp uptick in heart disease rates starting in 1920, one could imply that animal fat consumption must have increased significantly since that year to correlate with the rise in heart disease. However, the consumption of saturated animal fats in America declined steadily during that period, while use of vegetable fats increased dramatically.
Numerous studies, both national and international, have explored this topic. Let’s look at a few of them.
High Cholesterol Means High Risk…Right…?
Any discussion on the causes of heart disease starts with the assumption that high LDL cholesterol levels are a key indicator of risk. However, there is little evidence that high cholesterol alone leads to cardiovascular disease. A research article called, The Fallacies of the Lipid Hypotheses, cited autopsy studies that found no association between high cholesterol levels and atherosclerotic plaque. The article also cited several more studies that, in summary, showed that high cholesterol was not found as a risk factor in existing patients with diabetes, or heart disease, or renal failure, or older people. It’s articles like these that reveal a much broader implication: that a vast amount of research on this topic is unknowingly misleading the scientific community. And, even more so, the general public: Such studies showing that “x” food should be avoided because it causes high cholesterol, are not only vilifying the wrong foods but also driving the USDA’s Dietary Guidelines for Americans. Yikes.
Rather than looking at high cholesterol, a better question these researchers should be asking is, “What causes high LDL particle number?” What’s more indicative of CHD risk is not the total concentration of cholesterol but rather the number and size of LDL particles. LDL particles carry cholesterol through the bloodstream. Smaller, denser LDL particles are considered more atherogenic (plaque-building) than larger ones because they are better able to enter the walls of the arteries. Additionally, a high number of these particles can significantly increase risk of cardiovascular disease (CVD) even if total LDL cholesterol is within normal range. Oftentimes, total cholesterol levels mirror LDL particle size and number (meaning that when one is high, the other is high and vice versa). But sometimes these values are opposite – a person can have normal cholesterol levels but have high numbers of small LDL particles thus putting them at increased risk for heart disease but without being treated for it. Unfortunately, this pattern is often seen in those with a collection of cardiovascular risk factors (also called metabolic syndrome). The inverse of this can also be true: people can have elevated LDL cholesterol but low LDL particle number. These folks are not at risk of heart disease yet are usually (and inappropriately) prescribed cholesterol lowering medications. Given all of this, it is best to test for LDL particle number (called LDL-P) along with total cholesterol (LDL-C) to get a truer picture of your CVD risk.
Saturated Fat Isn’t the Enemy Either
A randomized control trial called the Sydney Diet Heart Study found that consuming omega 6 fatty acids, which is an unsaturated fat, increased the rates of death from all causes, coronary heart disease, and cardiovascular disease as compared to a diet that included saturated fats. This study (and others like it) showed that omega 6 fatty acids indeed lowered blood cholesterol but it did not translate to a lower risk of death from CHD. Interestingly, the study’s original aim was to prove the opposite effect. Two other controlled trials similarly failed to find any reduction in mortality from CHD after following a diet high in omega 6 fatty acids: Corn Oil in the Treatment of Heart Disease and the Minnesota Coronary Experiment. This latter study (from Minnesota) found a 22% higher risk of death for each 30 mg/dL reduction in blood cholesterol levels.
A Japanese prospective study that followed 58,000 men for an average of 14 years found no association between saturated fat intake and heart disease, and an inverse association between saturated fat and stroke (meaning that those who ate more saturated fat had a lower risk of stroke). Likewise, a meta-analysis of 21 studies involving nearly 350,000 participants showed no significant evidence that dietary saturated fat is associated with an increased risk of cardiovascular diseases.
Other U.S. studies — the Veterans Clinical Trial, the Honolulu Heart Program, and the Puerto Rico Heart Health Study — found no significant relation between a diet high in cholesterol and saturated fats with CHD.
The Water Can Get Muddy
Whenever people research the connection between a nutrient and a disease, the water tends to get muddy. A lot of it has to do with asking the right question: Are they looking at total cholesterol as a marker of risk or are they looking at LDL particle number as well? Another reason is not taking other variables into account: Are other food compounds impacting risk or is it only saturated fat or cholesterol levels? If researchers aren’t looking for it, they won’t find it. Perhaps they’re looking in the wrong spot.
When it comes to saturated fat in particular, a couple of missing pieces come to mind:
Most studies on saturated fats do not look at the type of saturated fat consumed. For example, palmitic acid (found in processed meats) is more prone to raise cholesterol levels than stearic acid (found in hard cheeses) although they are both saturated fatty acids. Study participants who eat one type of saturated fat more than another type will unknowingly affect the research outcomes in different ways. Besides, as we’ve learned earlier, is saturated fat really the problem?
Secondly, studies don’t commonly look at the various nutritional profiles of the foods consumed. For example, a research article on coconut oil, which is purely saturated fat, found that it reduced inflammation of the blood vessels, lowered blood pressure, and lowered oxidative stress which provides an overall cardio-protective effect. Furthermore, coconut oil lowers total and LDL cholesterol while increasing HDL. It’s thought that the heavy antioxidant content in coconut oil (specifically its polyphenols) is what lowers these various risk factors for CVD. Cheese and yogurt are another example. They are also saturated fats, but they contain nutrients like vitamin K2 and probiotics. Both of these nutrients may lower heart disease risk through their effects on blood sugar, cholesterol levels, and inflammation. Study participants who eat more cheese and yogurt than red meat could introduce a confounding factor that can heavily affect research results and lead to misleading conclusions.
So What’s the Real Danger?
So if it isn’t saturated fats and cholesterol, then what causes heart disease? There are, in fact, a number of compelling studies and theories that culminate in a list of dietary and lifestyle factors linked with heart disease risk:
Excess Sugar
As early as the 1950s, a link was first discovered between refined sugar and heart disease. Sugar consumption lowers the body’s resistance to bacteria, viruses, and yeasts that may cause inflammation in both the heart and the arteries. Furthermore, excess sugar leads to deficiencies in the entire B-vitamin complex, needed for healthy arteries. Ongoing research at the USDA indicates that fructose (mainly in the form of high-fructose corn syrup (HFCS)) is even more dangerous than sugar.
Deficiencies in B Vitamins
There is a positive relationship between deficiencies in folate, B6, and B12, and the severity of hardening or stiffness of the arteries, as well as the buildup of arterial plaque. Furthermore, high homocysteine is considered an independent risk factor for atherosclerosis, heart attack, and stroke. High homocysteine levels can arise when intake of these B vitamins are low.
Vitamin C Deficiency
can compromise our blood vessel lining making them more prone to inflammation and tearing. A diet rich in vitamin C helps maintain the integrity and function of blood vessel walls and helps lower hypertension. In the EPIC Norfolk study, 14,000 adults were followed for 11 years and found that borderline low vitamin C plasma levels were associated with a 40% higher risk of heart disease compared to those with sufficient plasma levels. Deficiencies occur in diets that lack fresh fruits and vegetables.
Deficiencies in Electrolytes
Heart disease rates are lower in regions where drinking water is naturally rich in trace minerals, particularly magnesium, which acts as a natural anticoagulant. Calcium also plays a role in protecting the heart and arteries, while potassium helps maintain proper blood pressure.
Omega 6 Fatty Acids, in Excess
A danger of vegetable oils and seed oils is their higher amount of omega 6 fatty acids in relation to omega 3 fatty acids. Omega 6 fats are polyunsaturated fats found in large amounts in oils such as corn, soybean, safflower, sunflower, cottonseed, and canola. A systemic review of over 60 studies found that excess consumption of omega-6 fatty acids increases the amount of oxidized cholesterol in arterial plaque. Oxidation occurs when vegetable oils are heated, thus producing free radicals.
Vitamin D Deficiency
A deficiency in this vitamin is associated with calcification of the arteries. Unfortunately, synthetic vitamin D added to milk and cereals have the same effect as vitamin D deficiency — they both cause abnormal calcification of the soft tissues, particularly the blood vessels. Our bodies can manufacture vitamin D from cholesterol through the exposure to sunlight, but dietary sources or supplementation give added protection. Vitamin D3 (the active form) is found only in animal fats.
Antioxidant Intake
Specifically beta-carotene and vitamin E may protect against damage from oxidized cholesterol and inhibit its formation. Sweet potatoes, carrots, butternut squash, and dark leafy greens supply beta-carotene (and hundreds of other carotenoids), while wheat germ oil, sunflower seeds, almonds, avocado, and dark leafy greens are an excellent source of vitamin E.
Specific Lifestyle Factors and Health Conditions
These include lack of exercise, poor thyroid function, certain bacterial or viral infections, intestinal permeability (leaky gut), excess body weight, high blood pressure, smoking, and kidney disease.
From this, we can see an association of heart disease with the increased consumption of sugar and fructose, nutrient-stripped foods, and processed vegetable oils. In addition, various deficiencies due to a lack of nutrient-dense vegetables, fruits, and proteins are further associated with heart disease risk. So what do we do about it?
Action Steps:
With all this in mind, we can mitigate the risks of developing heart disease and other forms of cardiovascular disease by making these dietary changes:
Replace Vegetable Oils with Healthy Fats
Start by tossing out vegetable oils and switching over to anti-inflammatory oils. Vegetable oils to avoid include canola oil, safflower oil, palm oil, soybean oil, sunflower oil, corn oil, vegetable shortening, margarine, and any other plant based spreads. In contrast, anti-inflammatory oils to purchase would include extra virgin olive oil, avocado oil, grass-fed butter and ghee, walnut oil, flaxseed oil, and coconut oil (in moderation). When it comes to avoiding harmful oils, reading ingredients labels becomes key. Never believe the splashy claims on the front of the packaging – I’ve seen mayonnaise that, despite its claim of having olive oil (which it does), it also contains canola oil (which it shouldn’t). Without reading the ingredients list, a person would probably buy the mayonnaise thinking they were avoiding harmful oils. Most salad dressings, creamy sauces, chips and crackers, and any “junk food” will contain harmful oils so it’s always important to read what’s in them!
Lose the Sugar
Severely limit (or avoid!) all sources of sugar unless they come from raw honey, whole fruit, or plain yogurt. This includes table sugar as well as items such as coconut sugar, raw sugar, and high fructose corn syrup. At the very least, make sure the amount of sugar in any item is less than 7 grams per serving. Do not exceed 12-15 grams of sugar per day. Stevia, monk fruit sweetener, and allulose are natural sweeteners (not artificial) and can be good alternatives to sugar in moderation.
Eat Your Veggies
Eat a variety of colorful, nutrient dense vegetables and fruits. Aim for 5 servings of vegetables per day and 1-2 servings of whole fruit. Also prioritize organic sources of protein including eggs, fish, poultry, and grass fed beef.
Cardiovascular disease, which includes heart disease, heart attack, stroke, and all associated risk factors including LDL cholesterol particle number, high blood pressure, high homocysteine, and high insulin, is multifaceted with several factors contributing to its formation. The original assumption of having high cholesterol or eating a diet high in saturated fats and cholesterol has come under intense scrutiny as the cause of cardiovascular disease given the body of evidence in large-scale studies proving otherwise. Unfortunately, the dietary advice that came out of these original (and incorrect) assumptions has led away from animal-based natural food sources and towards a diet full of processed grains (and thus added sugar), inflammatory seed oils, and synthetic additives – the very things that promote and perpetuate the health condition we’re trying to avoid! Fortunately, with this knowledge, we can make conscious dietary changes that focus on whole foods and help lower our risk of cardiovascular disease.