Lipids and Heart Disease

We've been learning about atheroma (artery disease) and what causes it. A major driver is the cholesterols that go zooming through your blood stream. HDL = "High Density Lipoprotein" (eg the Good kind); LDL = "Low Density Lipoprotein". Lipoproteins are fatty acids, or giant molecules that move cholesterol throughout the body. Also present are Very Low Density Lipoproteins, also called Triglycerides, and they are perhaps more bad than LDLs. The key is trying to get the body to produce more HDL, and less LDL and VLDL.

Here's a bit more research on Lipids, mostly from Wikipedia.

Because LDLs transport cholesterol to the arteries and can be retained there and can start the formation of plaques, increased levels of LDLs are associated with atherosclerosis, and thus heart attack, stroke, and peripheral vascular disease. For this reason, cholesterol inside LDL lipoproteins is often called bad cholesterol. This is a misnomer. The cholesterol transported on LDL is the same as cholesterol transported on other lipoprotein particles. The cholesterol itself is not bad; rather, it is how and where the cholesterol is being transported, and in what amounts over time, that causes adverse effects.

Increasing evidence has revealed that the concentration and size of the LDL particles more powerfully relates to the degree of atherosclerosis progression than the concentration of cholesterol contained within all the LDL particles. The healthiest pattern, though relatively rare, is to have small numbers of large LDL particles and no small particles. Having small LDL particles, though common, is an unhealthy pattern; high concentrations of small LDL particles (even though potentially carrying the same total cholesterol content as a low concentration of large particles) correlates with much faster growth of atheroma, progression of atherosclerosis and earlier and more severe cardiovascular disease events and death.

A 4 minute animation of the atherosclerosis process, entitled "Pathogenesis of Acute MI", commissioned by Paul M. Ridker, MD, MPH, FACC, FAHA, at the Harvard Medical School, can be viewed at pri-med.com By Clicking Here.

Lowering LDL
The use of statins (eg Lipitor, or in my case, Zocor), is effective against high levels of LDL cholesterol. Statins inhibit the enzyme HMG-CoA reductase in the liver, the rate-limiting step of cholesterol synthesis. To compensate for the decreased cholesterol availability, synthesis of LDL receptors is increased , resulting in an increased clearance of LDL from the blood. In other words, these drugs force the liver to create larger Lipid particles which is better for your heart health.

Clofibrate is effective at lowering cholesterol levels, but has been associated with significantly increased cancer and stroke mortality, despite lowered cholesterol levels.

Niacin (B3), lowers LDL by selectively inhibiting hepatic diacyglycerol acyltransferase 2, reducing triglyceride synthesis and VLDL secretion through a receptor HM74 and HM74A or GPR109A. Yeah, what he said. Just know that it works.

Tocotrienols, also called Vitamin E, have been shown to be effective nutritional agents to treat high cholesterol in vitro in recent research programs. They suppress the production of a specific enzyme which results in less cholesterol being manufactured by liver cells. This decrease in hepatic (liver) LDL levels causes hepatic LDL receptor up-regulation, further decreasing plasma LDL levels as it is taken in by the liver.

Dietary
Insulin, driven by the ingestion of carbohydrates, stimulates the production of cholesterols, while glucagon, driven by ingestion of protein, reduces the production of cholestrols. Glucagon levels are very low when insulin levels are high. A ketogenic diet (eg Adkins diet) may have similar response to taking niacin (lowered LDL and increased HDL).

Lowering the blood lipid concentration of triglycerides helps lower the amount of LDL, because Triglycerides (also called "Very Low Density Lipoproteins" or VLDL) gets converted in the bloodstream into LDL.

Fructose, a component of sucrose as well as high-fructose corn syrup, increases LDL synthesis.

Dietary Fiber
The main action of dietary fiber is to change the nature of the contents of the gastrointestinal tract, and to change how other nutrients and chemicals are absorbed. Soluble fiber binds to bile acids in the small intestine, making them less likely to enter the body; this in turn lowers cholesterol levels in the blood. Soluble fiber also reduces the absorption of sugar, reduces sugar response after eating, normalizes blood lipid levels and, once fermented in the colon, produces short-chain fatty acids as byproducts with wide-ranging physiological activities. Although insoluble fiber is associated with reduced diabetes risk, the mechanism by which this occurs is unknown. Not yet formally proposed as an essential macronutrient, dietary fiber is nevertheless regarded as important for the diet, with regulatory authorities in many developed countries recommending increases in fiber intake.

Importance of antioxidants
Because LDL appears to be harmless until oxidized by free radicals, it is postulated that ingesting antioxidants and minimizing free radical exposure may reduce LDL's contribution to atherosclerosis, though results are not conclusive.

Triglycerides
Triglycerides are formed from a single molecule of glycerol, combined with three fatty acids on each of the OH groups, and make up most of fats digested by humans.
Triglycerides, as major components of very low density lipoprotein (VLDL) play an important role in metabolism as energy sources and transporters of dietary fat. They contain more than twice as much energy (9 kcal/g) as carbohydrates and proteins.

Fat and liver cells can synthesize and store triglycerides. When the body requires fatty acids as an energy source, the hormone glucagon signals the breakdown of the triglycerides to release free fatty acids. As the brain cannot utilize fatty acids as an energy source (unless converted to a ketone), the glycerol component of triglycerides can be converted into glucose , via gluconeogenesis, for brain fuel when it is broken down. Fat cells may also be broken down for that reason, if the brain's needs ever outweigh the body's.

The American Heart Association notes that diets high in carbohydrates, with carbohydrates accounting for more than 60% of the total caloric intake, can increase triglyceride levels.

Increased exercise and reduced carbohydrate consumption ameliorate one potential cause of insulin overproduction to help maintain sensible triglyceride levels. Triglyceride levels are also reduced by omega-3 fatty acids from fish, flax seed oil and other sources. Recommendation in the U.S. is that one ingest up to 3 grams a day of such oils. In Europe the recommendation is for up to 2 grams. However, omega-3 consumption should be balanced with omega-6 fatty acids, ideally in a ratio between 1:1 and 4:1 (i.e., no more than four grams omega-6 for every one of omega-3).

Daily ingestion of omega-6 fatty acids, more than 1 gram of niacin (i.e., a mega-dose of vitamin B-3) and statins may also help improve triglyceride levels. It has been found that residents in Western countries do not ingest sufficient quantity of food with omega-3. The ideal ratio is almost never met, and the ratio is often too high, about 12 in France, up to 80 among whites in the U.S. and Canada. Omaga-6 fatty acids can be found in many grain oils such as sunflower, safflower and flax seeds.

Unused saturated or monounsaturated fatty acids accumulate in the body in the form of triglycerides that do not participate in the metabolism of the body.
In some cases, fibrates have been used to bring down triglycerides substantially.

Alcohol abuse can elevate triglycerides levels. (More on that in the next post). Just one drink can increase triglycerides in susceptible people. If you have elevated triglycerides and consume alcohol - a reduced intake or not drinking alcohol at all is strongly advised.

So, let me summarize:

1. Not all Lipids are bad.
2. HDL's are best.
3. LDL's and Triglycerides (VLDL) are worse in terms of heart disease.
4. You can minimize LDL/VLDL with:

• Drugs (statins)
• Suppliments (Niacin/B3, Vitamin E, and Omega-3 (fish oils) and Omega-6 (grain oils) fatty acids.
• Fiber (lots of sources)
• Exercise lowers insulin levels which lowers the LDL/VLDL production.
• Diet (lowering carbohydrates) will have a similar effect.

Next up: Demon Rum!

I Heart You!

Today is the "Heartiest" day of the year! Happy Valentine's Day to everyone I care about!

And a shout out to President Bill Clinton, who had his own heart issues addressed this week.

I'm nearly into month 5 of my “second round” of life after my heart attack. I have been reading a lot about heart disease and what may have caused my problem, not just to reduce my chances of another "big one", but to understand how others may reduce their risk of this kind of event.

What follows is some research I did online, mostly from Wikipedia (I love that place!)

Ather-what?

Technically, my heart attack was caused by a blockage of the Left Anterior Descending artery which provides about 50% of the fresh blood to the Left Ventricle of the heart. It was most likely caused by an atheroma, which is an accumulation and swelling in artery walls that is made up of cells or cell debris, that contain lipids (cholesterol and fatty acids), calcium and a variable amount of fibrous connective tissue. It is an unhealthy condition, but is found in most humans. The overall result of the disease process is termed atherosclerosis or "hardening of the arteries."

In developed countries, with improved public health, infection control and increasing life spans, atheroma processes (artery hardening) have become an increasingly important problem and burden for society. Atheroma continue to be the number one underlying basis for disability and death, despite a trend for gradual improvement since the early 1960s (adjusted for patient age). Thus, increasing efforts towards better understanding, treating and preventing the problem are continuing to evolve.

According to United States data, 2004, for about 65% of men and 47% of women, the first symptom of cardiovascular disease is heart attack or sudden death (death within one hour of symptom onset.) Read that one again, slowly.

Most artery flow disrupting events occur at locations with less than 50% lumen narrowing (they were not totally blocked before the attack). From clinical studies published in the late 1990s to IVUS (in-the-artery-ultrasound) to visualize disease status, the typical heart attack occurs at locations with about 20% stenosis (narrowing), prior to sudden lumen closure and resulting heart attack. Cardiac stress testing, traditionally the most commonly performed non-invasive testing method for blood flow limitations generally only detects lumen narrowing of ~75% or greater, although some physicians advocate that nuclear stress methods can sometimes detect as little as 50%.

My translation

Most/all people have some atheroma, which begins at a young age. The conditions for a heart attack are difficult to discover before it happens. Most people will have their first indication of heart problems by having a heart attack or dying from it. Our culture lets people live longer, but the lifestyle is conducive to athersclerosis.

Well.

That's not very encouraging.

I mean, if I had been screened, even including a cardiac stress test, they probably would not have found any reason for alarm. I was reasonably healthy. I ran 20 miles each week but was a bit overweight, with a BMI of 29.4, which is the top of Overweight category. Incidentally, to make it into the "normal" weight category, I'll have to lose 30 pounds. I'm shooting for more like 20, given that I do have more muscle from running. Last time I was that skinny, I was, well, pretty skinny.

Back to the whole prevention thing: My diet was pretty high in fats, particularly those from the chicken wing and burger/fries sections of the food pyramid. I also drink wine and beer which we will see in a couple posts drives triglycerides high...but I'm jumping ahead.

Had I been able to get a PCP checkup before the attack, I don't know if they would have seen this one coming. Other than telling me to lose weight, drink less and eat better, I'm not sure I would have received the kind of medical attention or medications that I'm currently taking, or that it would have prevented the heart attack I had in October 2009.

How to lower risk?

I kept digging. Given that you can't necessarily tell if you are likely to have a heart attack, it's best to follow a path of prevention.

Many approaches have been promoted as methods to reduce atheroma progression:
(a) food choices (like eating fish and fish derived omega-3 containing fats),
(b) abdominal fat reduction (which has a significant effect on cholesterol behavior)
(c) aerobic exercise (burns fat, lowers blood glucose, gives you that nice buzz),
(d) inhibitors of cholesterol synthesis (known as statins, like Lipitor),
(e) low normal blood glucose levels HbA1c below 5.0 (Avoid Type 2 Diabetes onset)
(f) micronutrient (multivitamin and magnesium) supplements

It was mentioned that cholesterol is not the villain that causes atherosclerosis. From clinical treatment trials, changing lipoprotein physiology (good/bad mix), and lowering blood sugar levels have proven to have the most dramatic impacts on reducing cardiovascular events and death rate from atherosclerotic disease.

Summary:

- It could happen to anyone
- Not a lot of warning signs in many cases
- Staying thin, exercising and eating the right stuff lowers risk

In the next posting, I'll get into the dirty details about Lipids (eg cholesterol) and factors that influence the mix of so-called “good” and “bad” cholesterol.