Saturday, 23 February 2013

Cholesterol, Part 1

Are you scared of Cholesterol? 


Why do we hear so much about trying to lower our cholesterol levels?  The story told by most doctors and drug companies is that  eating animal products that contain saturated fat and cholesterol clog your arteries and cause heart disease.  Saturated fats are solid at room temperature and will clog up your kitchen sink if you try and pour them down the drain so they will do the same thing in your blood vessels.  ( Even though you blood vessels are 15 C warmer than your kitchen pipes)  The scientists who believed cholesterol caused heart disease knew that analogy was ridiculous.  Their theory was that when there is too much cholesterol in the blood it gets stuck in the arterial wall which leads to the build up of plaque and atherosclerosis.

This Means War!

There is a  group of doctors and scientist who are waging a war on cholesterol.  They are trying to get your cholesterol levels as low as possible.The seem to believe that any amount of cholesterol is dangerous and their views can be summed up in the following quote:  "Eating foods that contain any cholesterol above 0 mg. is unhealthy"   T. Colin Campbell, PhD, author of The China Study

There is another group of "Cholesterol Skeptics" who say that cholesterol has nothing to do with heart disease.  They claim that measuring cholesterol at all is a waste of time.  I was confused so I started looking for the truth.  What I found that was there was some truth to both sides.  High cholesterol does not cause heart disease but the metabolism of cholesterol does play a role in heart disease.  I will expand on the latest theories of heart disease in this blog post series.  I found two websites that had a lot of well referenced material run by two incredibly smart people.   Chris Masterjohn, PhD  at his website "Cholesterol and Health" and Peter Attia, MD at his website "The Eating Academy" 

So what is cholesterol??  Is it really a dangerous substance?

Cholesterol is one of the most important molecules in the human body.  Every cell in your body has the ability to make cholesterol since every cell in your body needs cholesterol.  It is a critical part of cell membranes and is essential to cell membrane permeability.(1)

Cholesterol is needed for brain function.  It is involved in the development of synapses,(2) which enables brain cells to communicate with one another.  It is essential for myelin membrane growth which insulates neurons. (3)  The brain represents 2% of the mass of the  human body but it uses 25% of the cholesterol.  Cholesterol is vital to brain health.

Cholesterol is a precursor to all steroid hormones, which include sex hormones and adrenal hormones.(4)

Cholesterol is a precursor to Vitamin D.(5)

Cholesterol is essential to bile acid production which is used to digest and absorb fats and fat soluble vitamins.(6)

What happens to us if we don't have enough cholesterol?

Smith-Lemli-Opitz Syndrome (SLOS) is a metabolic disorder in which sufferers can not make enough cholesterol to support normal growth and development.  Symptoms of SLOS include mental retardation, poor growth, cleft palate, malformed genitals, extra fingers and toes, heart defects, hearing or sight loss and autism.  The most serious cases (produce almost no cholesterol) are spontaneously aborted during pregnancy or die a few months after birth. (8)

Low Cholesterol levels have also been linked to cancer (9), Depression and suicide (10), stroke (11), Infectious disease (12), autoimmunity (13), inflammation (14), and premature birth (15).

What about high cholesterol.

So we know cholesterol is an essential molecule but is too much cholesterol dangerous. Familial Hypercholesterolemia (FH)  is a genetic defect in which cholesterol levels are extremely high.  People with FH have an increased risk of heart disease.  This would suggest that high cholesterol is involved in heart disease.

But we also know that people with low cholesterol also get heart disease.  If high cholesterol causes heart disease how could you get heart disease if you had low cholesterol.  A 2008 study found that 73% of patients admitted to hospital with coronary heart disease had normal or low cholesterol levels. (16)  

Will eating eggs kill me

Many people do not eat eggs because they are trying to keep their cholesterol low.  Does eating cholesterol raise your cholesterol?  It turns out that cholesterol consumption has no effect on blood cholesterol for 70% of people.  Since about 75% of the cholesterol we need is made by our body if we eat more cholesterol our bodies respond by making and absorbing  less.  There is a slight increase in blood cholesterol in 30 % of people, but their HDL (the so called good cholesterol) goes up as much as their LDL  (so called bad cholesterol) so their cholesterol ratios actually get better.  

Even Ancel Keys, the father of the "lipid hypothesis", knew that eating cholesterol does not cause heart disease.  In 1997 he stated:

“There’s no connection whatsoever between the cholesterol in food and cholesterol in the blood. And we’ve known that all along. Cholesterol in the diet doesn’t matter at all unless you happen to be a chicken or a rabbit.”

Dr. William Castelli, the director of the Framingham Heart Study, stated in a 1992 editorial that:

 "... in Framingham Mass., the more saturated fat one ate, the more cholesterol one ate, the more calories one ate, the lower the person's serum cholesterol ... we found that the people who ate the most cholesterol, ate the most saturated fat, ate the most calories, weighed the least and were the most physically active."

So as you can see cholesterol in not an evil toxin.  It is a vital molecule that is needed for life.  In the next post we will examine how it came to be regarded as a dangerous substance.

Sunday, 17 February 2013

What Paleo Means To Me

I am often asked, what is the Paleo diet?  When most people think of the Paleo diet they think about eating a lot of meat like a caveman.  To me, Paleo is more of a lifestyle than a diet. It includes exercise, sleep, and sun, as well as diet.  The book I recommend most to people when they ask about it is "The Paleo Solution" by Robb Wolf.  He is a very entertaining writer who packs a lot of well referenced information into a book that is fun to read.

Although animal protein plays a large role in the Paleo diet, it is much more than just eating meat like a caveman.  Since I started eating a Paleo/Primal type diet the biggest difference isn't an increase in the amount of meat I eat, it is an increase in the amount of vegetables I eat.  Most people eating a Paleo diet will eat more vegetables than a lot of vegetarians (if the vegetarians rely on grains and legumes for most of their calories.)

Nutrients, not Anti-Nutrients.

For me there are two main goals in a Paleo diet; 1. Reduce inflammation by eliminating problematic foods, 2. Eat the most nutrient dense foods available. 

All living things have a way of defending themselves from predators.  Animals have claws and fangs to fight back, they have legs so they can run away.  Plants don't have any of these defenses so they rely on chemical warfare to protect themselves.  They have things like phytates that bind minerals (1), phytoestrogens that disrupt predators reproductive systems (2), they have saponins (3) and lectins that can damage the digestive systems (4).  Probably the most problematic for humans are prolamines, large proline rich proteins that are very hard to digest.

But I don't have Celiac!

The most well known of these proteins in gluten. Gluten is found in wheat, rye and barley.  Gluten is best known for causing Celiac Disease, an autoimmune disease in which the immune system starts attacking the lining of the small intestine (5).  The latest research is indicating that gluten may be involved in all autoimmune diseases (6).  The lining of the digestive tract is designed to keep large undigested molecules from being absorbed.  Gluten causes the release of zonulin which damages the tight junctions in the gut causing intestinal permeability ( leaky gut) which enables large undigested molecules to leak into the blood stream.(7)  This antagonizes the immune system and results in inflammation and possible autoimmunity. 

All grains contain prolamines that can cause digestive distress and inflammation even if they don't contain gluten.  Some examples are: zein in corn, avenin in oats, and oryzenin in rice.  Although these proteins do not cause celiac, they can result in intestinal permeability and inflammation.  Avoiding all grains will reduce inflammation.

What about the musical fruit? 


Legumes also contain proteins that are hard to digest and can cause inflammation.  They also contain a lot of fibre which humans cannot digest, but we do have bacteria in our digestive tract that can digest some fibre.  It is this bacterial fermentation in our lower intestine that can cause the gas that led to beans being called "the musical fruit"  For these reasons, beans are not a good food for anyone with digestive issues.

Don't Vegetable Oils have a "heart healthy" stamp?


Industrial seed oils and vegetable oils ( corn oil, canola oil, safflower oil) are polyunsaturated fats that are high in omega 6 fatty acids.  Omega 6 is one of the essential fatty acids (omega 3 is the other) that we need to consume, but we don't need very much.  Omega 6 oils are inflammatory, while Omega 3 oils are anti- inflammatory.  Ideally we should be consuming Omega 6 and Omega 3 oils in a 1-1 or 2-1 ratio.  It is estimated that the average North American consumes a ratio of around 20-1 .  Excess Omega 6 vegetable oils can lead to systematic inflammation.(8) 

Polyunsaturated fats are also very unstable and oxidize easily, compared to monounsaturated and saturated fats.  It is ironic that vegetable oils get a heart healthy stamp since they cause inflammation and oxidation, two of the main components of heart disease!

We can all agree on sugar, right?


Ok, here's an easy one. About the only people that will disagree is the soft drink industry.  Sugar is bad, high fructose corn syrup is bad and agave nectar is probably worse,  'nuff said.

Cavemen didn't drink milk! 


This is where we have to start looking to science instead of just doing what cavemen did.  Many people do have problems digesting milk sugar (lactose) and some milk protein ( mostly casein ).  Dairy fat from cows that eat grass seems to be well tolerated by most people and has been shown to have health benefits. (10), (11), (12), (13)  Most `Paleo Gurus` are recommending ghee ( clarified butter ), as the sugar and protein has been removed and many are ok with high fat dairy like butter, whipping cream, cheese, full fat sour cream and full fat yogurt if it is well tolerated.  Grass fed is better and many recommend raw milk and cheese, although it is illegal in many parts of North America.  Mark Sisson from the "Marks Daily Apple" website was one of the first Paleo Guru's to allow high fat dairy in his version of Paleo (called Primal) that he wrote about in his book "The Primal Blueprint" 

OK, you took away my bread, pasta and french fries.  What am I supposed to eat?


Now that we have removed the problematic foods we get to the second part of the Paleo template, Eating the most nutrient dense foods on the planet.  The most nutrient dense foods are:

meat (especially organ meat and bone broth)
fish and seafood
healthy natural fats ( butter, animal fats, coconut oil, olive oil )
nuts and seeds
fermented foods (yogurt, kefir, sauerkraut)

Robb Wolf has stated that most people have eaten a lot of Paleo meals.  He points out that if you've ever had an omelet with some veggies in it for breakfast, that's Paleo.  If you've ever had a salad with some grilled chicken or fish on it for lunch, that's Paleo.  If you've ever had a grilled steak or ribs with some asparagus and a glass of red wine for dinner, that's Paleo.

But what about fibre?

Most nutritionists and dieticians will say that without grains you won't be getting your fibre.  Grains are actually not that good of a source of fibre, compared to vegetables.  They may point out that 100g of whole wheat bread has 6 g of fibre and 100 g of spinach only has 2 g of fibre.  This is true, but what they fail to tell you is that 100 g of bread has 278 calories and 100 g of spinach has 23 calories, so calorie for calorie spinach has much more fibre.  If you wanted to get your recommended 38g of fibre a day from whole wheat bread you would need to eat 1760 calories of bread, but you would only need to eat 437 calories of spinach to get the same amount of fibre.(14)  (15)

Isn't all that saturated fat and cholesterol going to give me a heart attack?


I plan on going into more detail about the myth that eating saturated fat and cholesterol cause heart disease in future posts and write about what the latest science is telling us about heart disease. 

For the purposes of this post I will just say that there has never been good evidence that eating saturated fat is unhealthy. A meta-analysis was done in 2010 on the association of saturated fat and cardio vascular disease. (16)  The study found:

"A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD."

For more information on saturated fat check out these blogs.(17)  (18)

Isn't the Paleo diet just another version of Atkins?


When most people switch from the standard grain based diet to a paleo/primal type they will reduce the amount of carbohydrates they consume.  This doesn't mean that Paleo has to be low carb, it's just that the standard grain based diet is very, very high in carbohydrates.  There is not a set level of carbohydrates for the Paleo diet.  The amount of carbs will vary from person to person.  People who are lean and active doing a lot of high intensity exercise are going to need to consume more carbohydrates to fuel these intense workouts.  People who are less active or do low intensity exercise can get more of their fuel from healthy fats.  People who have metabolic disorders, diabetes or want to lose weight would get the best results by starting on a low carb version of Paleo.  Later they may want to start to experiment with adding in some carbs and checking their blood sugar response. 

There was no single Paleo diet.


Another criticism I hear is that the Paleo diet varied a great deal depending on where in the world you lived.  Paleolithic people in the arctic ate a much different diet than Paleolithic people on a tropical island.  This is true but I think of this more as an advantage.  Paleo to me is not a strict set of rules, its more like a set of guidelines.  Chris Kresser calls it a Paleo Template.  Its a place to start but everyone has to experiment and find a version that works best for them.  A hard charging 25 year old athlete doing three hours a day of intense exercise is going to need to eat a lot more calories and carbohydrates than a 55 year old, overweight, inactive diabetic office worker.  A food pyramid that gives the same recommendations to both does not work.  Some can eat more fruit and starch while others have to limit them.  Some can have white rice, quinoa and lentils occasionally while others can't tolerate any.  Our bodies also change over time so we have to be flexible and willing to tinker with our lifestyle.

I'll never be able to eat in a restaurant again!!!


I believe in the 80/20 rule.  This means, although I try and eat 100% Primal, I don't worry about it if up to 20% of my meals aren't Primal.  Everyone has to figure out what 80/20 is for them.  Some can eat anything they want as their 20% and not get any large reactions.  Others may be bloated, get brain fog or sore joints from half a slice of bread.  It doesn't take long for most to realize that some foods are just not worth eating so they completely avoid them.  They adopt the 80/20 rule, but feel so much better when they eat Primal that they end up having more of a 90/10 or 95/5 rule.  I have autoimmunity issues so I am 100% gluten free. I try to make smart choices at restaurants but I don't want to be "That Guy" who can't eat anything whenever he goes out with friends. I recommend being strict for the first 30 days then experimenting to see what you can tolerate. 

Remember, diet is just part of the Paleo lifestyle.  Exercise, sleep and vitamin D from playing in the sun all contribute to good health.  Chronic stress can also be detrimental to health. Constantly worrying about what you eat can negate some of the positive affects of a good diet.  If you have a bad day and eat a lot of unhealthy food, don't worry about it, tomorrow is another day and a chance to make better choices.