Saturated Fat and The Diet-Heart Hypothesis
Avoid saturated fats and cholesterol because they choke our arteries.
This sounds a familiar advice.
And why not.
This has been the cornerstone of dietary advice for more than 50 years.
In a nutshell, ditch your butter, lard, eggs, cream, bacon, red meat and switch to low-fat and vegetable oils if you want to maintain your heart health and live longer.
But what if this all is a big mistake?
What if we tell you that saturated fats and cholesterol don’t increase your risk of cardiovascular disease?
What if opposite is true?
The western diet comprising of processed food is largely to be blamed for the obesity, diabetes and heart disease epidemic we are facing today.
But everyone from your cardiologist, nutritionist, family doctor, media and even your neighbor will tell you that saturated fat and cholesterol are your number one enemy and would cause heart attacks and cardiovascular disease.
But with saturated fat intake at an all-time low, how would you still explain the rise of cardiovascular problems in the country?
It all started when Ancel Keys, a scientist at the University of Minnesota, published a paper that supported an idea: Saturated fat raises LDL cholesterol in the blood, which causes heart disease – giving rise to diet heart hypothesis.
The traditional diet heart hypothesis predicts that when you replace saturated fats with vegetable oils, it will lower accumulation of cholesterol in the arterial walls – slowing the progression of atherosclerosis and reducing the risk of coronary heart disease.
Needless to say, the theory was immediately lapped by the health authorities, media and public alike.
Its wide acceptance immediately demonized the saturated fat and cholesterol.
Never in the history of medicine and nutrition a dietary advice has single-handedly transformed our dietary choices as this one.
As it turns out, it was all based on bad science.
Saturated Fat is Not Bad, Debunking the Diet Heart Hypothesis
First, the diet heart paradigm has never been established in a randomized controlled trial.
A relationship between saturated fat intake and cardiovascular risk has never been proven.
Second, an overwhelming body of evidence suggests otherwise.
Ironically, the advice to reduce saturated fats from the diet has, in fact, may have contributed to our heart problems.
What’s more, the studies show that saturated fats are protective, lower cholesterol levels in blood and contribute to weight loss. Surprised?
A 2010 meta-analysis of 21 prospective cohort studies found no significant evidence for concluding that dietary saturated fat puts one at an increased risk of heart disease. [2]
A 2010 Japanese study followed 58,000 men and women for an average of 14 years. The researchers found that is no association between saturated fat intake and mortality from heart disease. In fact, people who ate more saturated fatty acids were less likely to die from stroke. [3]
In 2012, researchers at the Norwegian University of Science and Technology followed 52,087 adults, aged 20-74, for 10 years and found that women with high cholesterol levels had lower ‘all-cause mortality risk’ than those with lower cholesterol. [4]
They also discovered that in women lower cholesterol levels increase the risk for heart disease and the authors concluded that “clinical and public health recommendations regarding the ‘dangers' of cholesterol should be revised.
This is especially true for women, for whom moderately elevated cholesterol (by current standards) may prove to be not only harmless but even beneficial.” [4]
In 2013, Aseem Malhotra, an eminent London cardiologist, reasoned that reducing your saturated fat intake increases your risk for obesity and cardiovascular disease. The article ‘Saturated fat is not the major issue’ was published in the British Medical Journal. [5]
In 2014, a meta-analysis, published in the Annals of Internal Medicine, summarized evidence about associations between fatty acids and coronary heart disease.
The review used data from nearly 80 studies and found no evidence to support the current guidelines that encourage people to consume polyunsaturated fatty acids while reducing their intake of total saturated fats. [6]
Now, a recent 2016 analysis published in BMJ again threw major doubts on the diet heart hypothesis.
This analysis is based on the old data from Minnesota Coronary Experiment, a five-year research that began in 1968 but the results were never published.
These results are found to be consistent with Sydney Diet Heart Study, an Australian study from the same time.
The 2016 analysis showed that [7]:
- People who consumed corn oil had lower cholesterol levels than the people eating diets rich in high saturated; but this didn’t improve their survival.
- Ironically, older participants with lowered serum cholesterol were found to have higher risk of death.
- Even more shocking was the observation that people consuming lots of vegetable oil were more likely to show signs of a heart attack upon autopsy than those eating more saturated fat.
The study authors concluded:
“Available evidence from randomized controlled trials shows that replacement of saturated fat in the diet with linoleic acid effectively lowers serum cholesterol but does not support the hypothesis that this translates to a lower risk of death from coronary heart disease or all causes. Findings from the Minnesota Coronary Experiment add to growing evidence that incomplete publication has contributed to overestimation of the benefits of replacing saturated fat with vegetable oils rich in linoleic acid.”
Despite all this evidence, this unproven theory has been aggressively promoted for more than four decades.
All this time we were assured that saturated fat is the primary cause of obesity, diabetes, and heart disease crisis and to cut back on fat intake to 30% of the total calorie intake and saturated fat to 10%.
What Happens When You Replace Saturated Fats with Vegetable Oils?
With the low-fat diet craze, we are now eating a lot more carbohydrates than ever before; and this includes grains, whole grain pasta, fruits and starchy vegetables, not to mention highly refined processed foods.
What is wrong with excessive carbohydrates?
In the body, carbohydrates are metabolized into glucose – which causes pancreas to release insulin.
While insulin signals muscle, liver, and fat cells to pick up and absorb glucose from the bloodstream and keep blood sugar levels in check, it also helps the body to store fat.
When you eat high amounts of carbohydrates, your body releases more insulin and after a point your cells become resistant to the effect of insulin (eventually causing insulin resistance, if you continue eating carbohydrate laden meals).
Consequently, your muscle and liver cells stop utilizing the available glucose, which is then stored or rather trapped in fat cells.
So, insulin sends signals to the fat cells to store fat and to lock it there – following a carbohydrate-rich meal.
It's also important to note that insulin is sensitive to both carbohydrate and protein, but not fat.
When you eat carbohydrate rich meal, insulin is released and signals the body to burn carbohydrates as fuel instead of using fat.
And when you eat fat, you produce no insulin and the body turns to fat to produce energy.
This association is known as carbohydrate-insulin hypothesis.
So, when you swap saturated fat with carbohydrates, (especially refined carbohydrates), you are increasing your chances of developing insulin resistance, obesity and type 2 diabetes.
It also increases the levels of triglycerides and small LDL particles, while reducing HDL cholesterol. [8]
Nina Teicholz, a journalist who launched an extensive research into the saturated fat and cholesterol theory, told the Wall Street Journal:
“The real surprise is that, according to the best science to date, people put themselves at higher risk for these conditions no matter what kind of carbohydrates they eat. Yes, even unrefined carbs. Too much whole-grain oatmeal for breakfast and whole-grain pasta for dinner, with fruit snacks in between, add up to a less healthy diet than one of eggs and bacon, followed by fish. The reality is that fat doesn't make you fat or diabetic. Scientific investigations going back to the 1950s suggest that actually, carbs do.” [9]
Sugar, Not Fat, Was the Culprit!
When you remove fat from diet, the flavor goes for a toss too.
The food industry replaced the saturated fats with added sugar to save the lost flavor.
While on one hand, saturated fat was being significantly reduced in our diet, added sugar in the modern diet has been at an all-time high.
These added sugars – including table sugar, high-fructose corn syrup (HFCS), brown sugar, honey, agave nectar or maple syrup – are added to processed foods to enhance their flavors and texture while also increasing their shelf-life.
Indeed, weight gain is just the tip of the ice-berg when it comes to counting the ways sugar can harm.
It causes inflammation and increases risk of cardiovascular disease, damages liver and leads to Alzheimer’s disease (dubbed as type 3 diabetes by many).
New research suggests that increased sugar consumption could be an independent risk factor for metabolic syndrome – a cluster of health conditions characterized by elevated blood pressure, high triglycerides, low HDL levels, high blood sugar levels and obesity.
Metabolic syndrome can lead to type 2 diabetes, which further increases inflammation and increases risk of heart diseases, stroke and even cancer.
Meanwhile, we also switched to vegetable oils.
It is well-known that over-heating vegetable oils create toxic oxidation products – that cause oxidative stress and inflammation.
For this reason, vegetable oils were made solid and more stable through a process called hydrogenation, leading to the production of trans fats.
Studies show that trans fats are even more harmful for heart health.
Found in ready made baked goods, salad dressings, margarine, micro-wave popcorn, French fries and chips, trans fats promote inflammation, the root cause of many chronic ailments including heart disease, stroke, insulin resistance and diabetes.
Trans fats are also known to trigger nutritional deficiencies and impair immune system functions.
Research from the Harvard School of Public Health and other sources indicates that trans fats can cause harm in even small amounts, “for every 2% of calories from trans-fat consumed daily, the risk of heart disease rises by 23%.” [10]
As the Food and Drug Administration is mobilizing a ban on trans fats, the bad news is food manufacturers are resorting back to using regular vegetable oils.
Certainly, these are not the health problems we bargained for when we wholeheartedly embraced the idea that saturated fat/cholesterol cause heart attacks while ditching butter, cheese, eggs and red meat along the way.
The Truth About Saturated Fat and Cholesterol
Your body needs saturated fat in healthy amounts to carry out a range of functions vital for health.
Most importantly, saturated fats act as building blocks for cell membranes, hormones and hormones like substances.
Fats keep us fuller for a long time.
They also play an important role in carrying fat- soluble vitamins A, D, E and K; vitamin D deficiency, in particular, is considered a risk factor for cardiovascular events (heart attack, congestive heart failure, peripheral arterial disease, stroke), diabetes and high blood pressure. [11] [12]
Adequate saturated fats are also important for:
- Heart health: as they help the body to lower levels of lipoprotein a or Lp(a), increase HDL cholesterol and contribute to overall weight loss.
- Bone health: as they help in calcium absorption
- Liver health: as they stimulate the liver cells to dump their fat reservoirs and also protect the liver from the toxic effects of alcohol and NSAIDs, commonly used to manage chronic pain and arthritis. Liver is one powerful detox machinery in our body and considering its other important functions in fat storage, metabolism and efficient absorption of nutrients, maintaining liver health is absolutely important to manage weight and maintain overall health.
- Brain health: as the myelin sheath, the protective coating around the neurons, is made of saturated fats (and cholesterol). The brain needs fats for proper functioning and repair.
- Immune health: as they help the white blood cells to identify and kill invading pathogens including viruses, bacteria and fungi.
With all these benefits, it is recommended that 40-50 percent of your calories must come from saturated fats versus a mere 10 % as suggested by mainstream health establishments.
Similarly, you also need cholesterol for many important biological functions.
In fact, levels of total cholesterol gone too low will increase your risk of cardiovascular disease.
Yes, you read that right.
