At the start of the month I published the first of two-part blog about cholesterol. If you haven't read the first then my suggestion is to go ahead and read that now (click here), before proceeding with this; the second part.
If you have read the first part then here we go with the concluding part of dispelling the 'cholesterol causes CHD myth' and hopefully addressing what does cause heart disease, strokes, and the like.
In Part One I explained what cholesterol is, what lipoproteins are (including high density and low density lipoproteins), I discussed that most cholesterol is necessary and produced in the liver, and that there is little to no relationship between cholesterol levels and heart disease or stroke.
Statins, memory loss, and why we should be loving cholesterol
At present the NHS pay a considerable amount of money to use statins to lower cholesterol in many individuals. In fact the cost is estimated in excess of £2 billion, which if redirected could could employ around 70,000 extra nurses per year, or build two brand new, fully equipped, state of the art hospitals. As I stated in the previous blog; Dr. Malcolm Kendrick goes in to considerable detail throughout his book "The Great cholesterol Con", and one area he doesn't skimp on is the potential harmful side effects of statins. I, however, am going to move on promptly and redirect you to his book, but rest assured the list of harmful side effects is long and VERY concerning, one of which is memory loss. This is where I'm going to linger for a second; whilst we can agree that memory loss is far from ideal there is research supporting the necessity of cholesterol in the brain in the which allows gllial cells to release cholesterol which allow synapses to form. Synapses are fundamental to neuronal function which essentially allow signals to pass to target cells. What this basically means is that without cholesterol in the brain we stop functioning right; thinking, remember, controlling movement, our senses get messed up and much much more.
In addition to all of this there is evidence to suggest that a low cholesterol level leads to reduced serotonin levels. Low serotonin levels are linked with depression, violence, self harm, suicide and aggression (follow the links to read articles/publications).
Ok so we know cholesterol is good, or at least that it isn't bad. But we now need to consider...
What causes heart disease....
So we know that things are going wrong on some kind of hormonal level; the three part hormonal system of body is the hypothalamus, pituitary gland, and adrenal glands; also known as the 'HPA-axis'. The HPA-axis is closely connected to the autonomic nervous system, which is divided into the sympathetic (which speeds up your heart rate, reduces saliva production, and sends blood to your muscles) and the parasympathetic (which basically does the opposite) systems. Notably the sympathetic nervous system also stimulates the liver to release glucose, pushing up blood sugar levels and essentially acts as your fight or flight response, releasing 'stress' hormones. It is often thought of as a catabolic state; you exercise, are burning energy stores and are not ready to eat. The parasympathetic nervous system causes insulin to go up and represents the anabolic state; all is well, eat food, store calories and so forth. Dr. Kendrick considers the concept of what happens if you are stressed? e.g. if both responses happen simultaneously? - you try to eat but you body sends blood away from your stomach, you have high levels of adrenaline and cortisol, adipose tissue would be under instruction to both absorb and release fat for energy, the liver would be trying to store and release glucose, and your blood sugar would be out of control with spikes of insulin as your body tried and failed to overcome the effects of the stress hormones. Phew. This is not good.
Fundamentally in this condition Dr. Kendrick is talking about a dysfunctional HPA-axis. He goes on to discuss tumours that can result in a highly dysfunctional system, he mentions cushings syndrome and explains that all of this ultimately relates back to increased cortisol levels. Cortisol a stress hormone. What does cortisol do? - triggers the liver to release glucose, stimulates breakdown of free fatty acids, breaks down muscle proteins in to amino acids, ultimately leaving you with high blood sugar levels and insulin resistance.
See here for a really nice article on stress and the HPA-axis! In addition this journal lists the causes of a dysfunctional HPA-axis as "...stress, emotional pain, lack of stability, constant change, neurotoxins (aspartame - we've talked about this before), diets high in sugar and caffeine..".
So what causes stress, well apart from winter and Monday mornings (no seriously, there is a higher rate of cardiac incident on Monday mornings!!):
"Framingham Heart Study results in Am J Cardiology published in 1987 also showed that hourly risk of sudden cardiac deaths was at least 70 percent greater between 7 and 9 AM than the average risk during the remaining 22 hours of the day. / In a study published in Circulation in 1993, data from the Berlin emergency care system found a peak frequency of ventricular fibrillation between 6 AM and noon; in contrast, asystolic episodes were more evenly distributed throughout the day. / Another study in Am J Cardiol published in 1992 showed that the morning peak in sudden death is particularly related to the first three hours after awakening and onset of activity. / Data from the Seattle Fire Department published in Circulation in 1998 also showed that a diurnal variation, with a low incidence at night and two peaks of approximately the same size. An evening peak at 4 to 7 PM was attributed primarily to patients found in ventricular fibrillation, while arrests that showed other rhythms exhibited mainly a morning peak from 8 to 11 AM. / Two studies published in Eur Heart Journal in 2000 and Am Heart Journal in 1999 showed that cardiac arrests also show a weekly and seasonal variation; the daily incidence peaks on Monday and the seasonal incidence is greatest in winter. / Another study published in the journal Circulation in 1999 showed that approximately 33 percent more deaths occur in December and January than in June through September"
Avoid smoking, and recreational drug use, and take some exercise (although the high intensity training (HIT) advocate in me needs to remind you that prolonged exercise (40 minutes +) increases cortisol levels to a point where your body is breaking down muscle proteins, etc, so make it intense and keep it short in duration.
Ultimately I've really enjoyed both reading the book, (and the other linked in articles) and writing this blog because it links back to so much of what I've written about previously; sugar intake is bad, too much exercise is bad, meat isn't bad, saturated fat isn't bad, exercise is essential; but should be high in intensity and low in duration (this way we stimulate physiological responses we want in strength and fitness, and steer clear of the ones we don't want), and so forth.
I guess at the end of all this you will elect to believe this or not, but I promise I will not get stressed out as to whether you do or don't either way.