So You Think Dietary Fat Causes Heart Disease?

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If you believe in unicorns, myth and mythology, you can continue to believe that fat in the diet causes heart blockages and heart attacks. If, on the other hand, you believe in science and evidence, you might want to question those beliefs. Because the evidence is in, and most people are wrong.

Bad science

So what was the problem to begin with? Americans made huge changes to their diets, the food industry changed its grocery store offerings, and lots of patients received rather severe tongue lashings from their doctors. All for no good reason. How could so many people be so wrong for so long?

Well, the answer is bad science.

Correlation is not causation

Scientists, including doctors, conduct trials to see if a particular theory or hypothesis is correct. Now, there are trials, and there are trials.

We have epidemiological studies, where segments of the population are followed for a number of years, and their health outcomes are noted. Observations are then made to see if those outcomes are correlated with certain habits or risk factors.

So what is the problem?

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Correlation is not causation. If two things are correlated, one does not necessarily cause the other. A rooster’s cry and the rising of the sun are correlated, but the rooster does not cause the sun to rise.

A murky beginning

The whole saga appeared to start in the 1970s. The Seven Countries Study by Ancel Keys revealed a strong correlation between the average amount of saturated fat in the diet, the average blood cholesterol levels, and the 10 year death rates from coronary heart disease (blockages in the heart arteries). Again, the key word is correlation. No cause and effect was proved.

However, what followed was an avalanche of government advice, and change in the food industry offerings. There were other epidemiological studies, but there was a lack of well-designed trials to support this undertaking.

What is a good trial?

Well, the gold standard is the so-called randomized controlled trial, often shortened to RCT. The details of such trials are beyond the scope of this article, but RCTs are better suited to look for a cause and effect relationship.

What were we told?

For over fifty years, we have been sold a bill of goods which was defective. And all of this based on epidemiological studies, of doubtful quality.

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Governments, and scientists, and doctors, told us that saturated fat was bad for us, that fat was bad for us. That consuming too much fat would cause blockages in the heart, leading to heart attacks, and premature death.

We were advised to cut down on fat, so that no more than 30% of our daily calories came from dietary fat. We were also told to limit saturated fat intake to no more than 10% of daily calories.

So what happened next?

Well, our calories come from carbohydrates, protein, and fat. If you eat less fat, you will tend to eat more of the other stuff. And that is what people did when they were asked to cut down on fat. They loaded up on carbohydrates. Not protein. Carbohydrates. In fact, in the late 20th century, the US government advised the public to start eating more carbohydrates, including 6-11 servings of grain products daily.

What next?

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Americans have dutifully heeded their government’s warnings about fat. Fat used to provide 40% of daily calories in the past. This has dropped to 30% in the last 30 years. But people have become heavier. Obesity rates have tripled in the last few decades. You don’t need data to know this. Just go to any mall or sports stadium and look around. Alarmingly, the incidence of type 2 diabetes has gone up many-fold.

So what is the problem?

It is clearly not dietary fat.

A meta analysis of prospective studies evaluating the association between saturated fat consumption and cardiovascular disease was published in the American Journal of Clinical Nutrition in January 2010. It analyzed 21 studies, which followed nearly 350,000 people over 5-23 years. It revealed that there was no significant evidence for concluding that saturated fat in the diet is associated with an increased risk of coronary heart disease or stroke.

Fat out, sugar in

Sugar

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The law of unintended consequences can be seen at work in this entire saga. Governments want less fat in the diet, so industry is urged to offer more low-fat products. But fat makes food taste good. Taking fat out worsens the taste. Thus, industry has been replacing fat with sugar, with results that we are seeing all around us: fatter people, with more diabetes. Also, we are witnessing a plateau in cardiovascular disease, which had been showing a decline for decades. And we may well see an uptick in this disease if things continue the way they are.

So is a calorie a calorie?

Not necessarily.

Food has metabolic consequences. A low-fat diet can lead to biological adaptations, such as increased feelings of hunger, a lower metabolic rate, and other components of a starvation response which tend to oppose weight loss.

Sugary drinks and sweets, as well as simple carbohydrates and starches, tend to increase blood levels of insulin, which is related to many chronic diseases, including diabetes and obesity.

Low-carbohydrate diets and low-glycemic index diets (with foods containing complex carbohydrates) tend to lower the levels of insulin in the blood, thus helping people maintain the weight loss they have achieved. Such diets might be protective against chronic diseases such as diabetes.

More recent studies

The Women’s Health Initiative Dietary Modification Trial revealed that over a mean of 8.1 years, a low-total fat diet did not significantly reduce the risk of heart disease or stroke in postmenopausal women.

The PREDIMED trial was a study of the Mediterranean diet in high risk people who were free from known coronary disease at the beginning of the trial. This study showed a 30% lower risk of having a major cardiovascular event in the higher- fat dietary groups compared with the low- fat control. This risk reduction is similar to that shown in the statin (cholesterol lowering drugs) studies, but at no cost to the health system!

Higher death rates?

A study by DD Wang and associates, published in JAMA Internal Medicine in August 2016, noted that men and women following low-fat/high-carbohydrate diets had higher rates of premature death, not lower.

Lesson learned?

Hardly!

The US government, through its Dietary Guidelines for Americans, 2015-2020, still recommends cutting down on saturated fat. These guidelines also state that a healthy eating pattern includes fat-free or low-fat dairy.

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School lunch programs in the US provide only low-fat milk. No whole milk is provided at all, although they do allow chocolate skim milk with its added sugars. And this is in spite of the Dietary Guidelines calling for a restriction on added sugar.

And the general public, of course, keeps buying low-fat everything. In fact, at most grocery stores, it is hard to find full-fat dairy.

And this is in spite of a study published in the reputable journal Circulation early in 2016 which found that people consuming full-fat dairy had a 50% lower risk of diabetes, compared to those consuming the low-fat variety.

So what to do?

  • Don’t obsess about fat. The link between fat, especially saturated fat, and heart disease is tenuous at best.
  • Trans-fat is still bad for you. This is found in cakes, pies, cookies, biscuits, crackers, and many fried or processed foods.
  • Try to eat whole or minimally processed foods.
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  • Include lots of fruits and vegetables in your diet.
  • Cut down on sweets and sugary drinks, as well as simple carbohydrates.
  • Include whole grains in your diet.
  • Eating an ounce of nuts daily is good for you.
  • Low-fat dairy has no benefits over the full-fat variety, and may well be worse, according to recent data.

And finally

Focus more on the overall dietary pattern.

As Dr. Mozaffarian, a leading researcher, says, “If something has a food label, it’s probably not the best choice. We need to move away from the idea that we can manufacture an artificially healthy diet.”

The Truth About Cholesterol: Good, Bad, and Ugly!

Do you really want to get rid of cholesterol? If somebody promised to remove all trace of it from your body, would you agree, thinking that that would eliminate the threat of heart disease? If you say yes, that would be a mistake. Because you would then find it difficult to survive.

What is cholesterol?

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It is all over the news, both TV and print, and tons of medical articles are devoted to this rogue. Except that it is not always a rogue.

“Chole” in Greek means bile, while “stereos” means solid. The “ol” signifies that it is an alcohol.

So cholesterol is a sterol, which is a modified steroid.

It is also a lipid molecule, which basically means that it is a type of fat.

Do we need cholesterol?

You better believe it!

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Why? Because it is an essential part of the cell membrane of all animal cells. Bacterial and plant cells have cell walls, which are fairly rigid. However, because of the cell membrane, animals, including us, can avoid having a cell wall. Thus animal cells can change shape and move around.

Anything beyond membranes?

Yes!

If you are Mycoplasma, you need cholesterol for growth. But if you are reading this, it is unlikely that you are Mycoplasma.

Assuming that you are a human being, you would need cholesterol for intracellular transport, cell signaling, and nerve conduction.

Vitamins and hormones

Unless you want to pop Vitamin pills and depend on hormone shots, you had better thank God for cholesterol.

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The synthesis of Vitamin D and all steroid hormones requires cholesterol. This includes sex hormones and adrenal gland hormones.

So should we eat a lot of cholesterol?

Hold on for a while.

If you are a man weighing 150 pounds (are there any of those around anymore?), your body makes about 1000 mg of cholesterol daily. Yes, makes. Since cholesterol is vital for the structure and functioning of the body, your body does not want to depend on your diet to give it enough of a supply.

Remember, the time of excess is relatively recent. For hundreds of thousands of years, human beings struggled to get enough food to survive and flourish.

So your body makes a lot of cholesterol. As we speak, your body (if you are the above-mentioned hypothetical male) contains 35 g of cholesterol. And most of it is not in the heart or arteries. It is mostly within the cell membranes, performing a vital function.

So how much should we eat?

Good question.

Let us turn to the Dietary Guidelines for Americans (DGA) which has been telling us what to eat and how much since 1980.

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In 2010, American men were consuming 350 mg of cholesterol daily, while women limited themselves to 240 mg. The DGA recommended that year that we should keep our intake below 300 mg/day. The rationale, of course, was that if we ate less cholesterol, our blood cholesterol levels would fall, and we would not develop blockages leading to heart attacks.

DGA 2015-2020 advice

The latest DGA report is revolutionary in one regard. It makes no recommendation to limit cholesterol intake.

The report states that “adequate evidence is not available for a quantitative limit for dietary cholesterol specific to the Dietary Guidelines.”

Say what?

Dietary cholesterol does not play a major role in blood cholesterol levels.

Yes, you heard that right.

The amount of cholesterol in your blood stream is not affected significantly by how much cholesterol you eat in your food.

Why?

Most of the cholesterol we eat is in the form of esters, and as such is poorly absorbed.

In addition, if we eat too much cholesterol, and a lot of it is absorbed, the body compensates by making less cholesterol on its own.

There are many factors which have a more pronounced effect on blood cholesterol than dietary intake of cholesterol.

Body weight, age, sex, physical activity, heredity, and consumption of saturated fats and trans-fats, all have significant effects on our blood cholesterol levels.

But what about heart disease?

That, of course, is the million dollar question.

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Links between high cholesterol levels and the development of coronary artery disease (blockages in the heart) leading to heart attacks are quite clear.

So what should we do to lower blood cholesterol?

And will that lead to prevention of heart attacks?

And what about the different types of cholesterol?

Conclusions

  • Cholesterol is not always bad.
  • Without cholesterol, we would not have cell membranes, some vitamins, and important hormones.
  • High cholesterol levels are associated with an increased risk of heart disease and heart attacks.
  • Cholesterol is of several types.
  • The level of cholesterol in your blood is not primarily dependent on how much cholesterol you consume in your diet.

Future direction

  • How best can you lower cholesterol?
  • Will that affect heart disease?

Stay tuned!

We will address these issues in subsequent posts.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

There are Fruits, and then there are Fruits

I love fruits. And you should, too. But all fruits are not the same.

It is estimated that Americans eat only about 42% of the recommended amount of fruits they should be eating.  Of the people who do consume fruits, the 2 to 30 year olds are drinking lots of fruit juice, accounting for more than half of their total fruit intake.

Fruit juice, anybody?

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So what’s wrong with fruit juice? For one, most fruit juices do not have any fiber. Secondly, most juices have too much sugar and calories.

Think about it. Have you ever heard of anybody overdosing on apples? When was the last time you said to your doctor, “Doc, I don’t eat much food. This five pound weight gain you are complaining about? Let me see. It must be all those apples I ate last month.”

The fiber in fruits gives you a sensation of fullness. So your stomach signals your brain to stop eating long before you have eaten 8 or 10 apples. And it keeps you from feeling hungry shortly after you quit eating.

However, if you drink apple juice, the absence of fiber prevents you from knowing when you have had enough. So you take in serious calories before your stomach protests. Just like those monster servings of soda they sell you at highway gas stations, with free refills.

Why bother with fruits?

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Fruits contain several important nutrients, which most people don’t get enough of.

  • Vitamins, including Vitamins A, C, K, and folate
  • Minerals, such as potassium and magnesium
  • Fiber
  • Anti-oxidants, such as poly-phenolic flavonoids, Vitamin C, and anthocyanins
  • Phyto-nutrients (plant derived micro-nutrients)
  • Fruits have no cholesterol and are naturally low in saturated fat, sugar and calories.

What are anti-oxidants?

Anti-oxidants are chemicals which donate electrons to free radicals and protect the body from damage.

Free radicals are chemicals which can damage cells and genetic material by “stealing” electrons from them. These radicals are generated by the body as a byproduct during the conversion of food to energy.

Polyphenols

These are chemicals produced by plants, fruits and vegetables. They have unique health benefits. Polyphenols are anti-oxidants, and can also fight inflammation and help protect us against some diseases, such as cancer.

They are found in fruits, vegetables, teas, coffee and wine.

What are flavonoids?

They are a family of polyphenols.

They are produced by plants as protection against parasites and harsh climates. They have many sub-classes, including anthocyanins.

Anthocyanins

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These are pigments which make plants purple and blue. They are powerful anti-oxidants.

Rich sources include blueberries, blackberries, blue-black grapes and plums.

Health benefits of fruits

  • The Harvard-based Nurses’ Health Study and Health Professionals Follow Up Study showed that the higher the average daily intake of fruits and vegetables, the lower the chances of developing cardiovascular disease.
  • People eating more than 5 servings of  fruits and vegetables daily had an approximately 20% lower risk of  coronary heart disease and stroke, compared to people eating fewer than 3 servings daily.
  • The DASH study (using a diet rich in fruits and vegetables and low in saturated and total fat)  showed a drop of 11 mm Hg in the systolic blood pressure (upper number) and 6 mm Hg in diastolic pressure (lower number) in patients with high blood pressure who followed this diet. Even many blood pressure medicines can bring about only this much drop in blood pressure.
  • Studies suggest a link between eating fruits and vegetables and protection against cancer. There is a suggestion that tomatoes may help protect men against prostate cancer.
  • Some studies suggest that eating more whole fruits (especially apples, grapes and blueberries) may lower the risk of type 2 diabetes.

Which fruits?

In general, any fruit is better than no fruit.

However, all fruits are not equal. Some are more equal than others.

Berries

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Blackberries, raspberries, strawberries, cranberries, blueberries and sour cherries are among the best fruits you can eat.

They have 30-50 calories per 100 gm fruit, and 4-5 gm sugar (blueberries have 10 gm and sour cherries 8 gm).

They are good sources of Vitamin B.

Strawberries, raspberries and blackberries are very good sources of Vitamin C, while cranberries, blueberries and sour cherries also have good amounts of it.

Blueberries and blackberries are quite high in Vitamin K.

Guavas

They are excellent fruits, with 68 calories per 100 gm, 5 gm fiber, 9 gm sugar, and abundant Vitamin C in particular. They are also good sources of Vitamin B and potassium.

Papaya

This is an often under-appreciated fruit. It contains 39 calories per 100 gm, 6 gm sugar, and abundant Vitamin C and Vitamin A.

Kiwi

This is an excellent source of Vitamin C and Vitamin K. It has 69 calories and 9 gm sugar per 100 gm.

Cantaloupe

This is a very good source of Vitamins C & K, and has only 34 calories per 100 gm, as well as 8 grams sugar.

Apricot, Honeydew, Grapefruit, Nectarine, Peach

With 36-48 calories and 7-9 gm sugar per 100 gm, these are good for health, and nice sources of Vitamin C. Grapefruits and apricots have ample stores of Vitamin A, too.

Pomegranate, Watermelon, Orange, Pineapple

These have 30 (watermelon) to 83 (pomegranate) calories and 6-14 gm sugar per 100 gm. They are particularly plentiful in Vitamin C.

Apple, Mango, Plum, Tangerine, Passion Fruit

They have 46-92 calories and 10-15 gm sugar per 100 gm. Mangoes have 15 gm sugar per 100 gm. Apples have 52 calories, 10 gm sugar and 2 gm fiber per 100 gm.

Pears, Bananas, Figs, Sweet Cherries, Grapes

These are relatively higher in sugar (10-16 gm per 100 gm), and have 58-89 calories per 100 gm. They are also good sources of vitamins.

Bottom Line

  • No single fruit has all the nutrients you need. It is therefore important to eat different kinds, and plenty of them.
  • The daily recommendation is for adults to eat one and a half to two cups of fruits.
  • You can use fruits as snacks, salads, and desserts.
  • It is better to eat whole fruits and those in season.
  • You can use fruits to top cereals and pancakes.

So go ahead and eat your fruits, instead of drinking them!

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