Cholesterol is a type of fat that is part of all animal cells. It is essential for many of the body’s metabolic processes. The body is very good at making its own cholesterol – it makes approximately 80% of your cholesterol.
Cholesterol is produced by the liver and also made by most cells in the body. It is carried around in the blood by little ‘couriers’ called lipoproteins. We need blood cholesterol because the body uses it to:
- Build the structure of cell membranes.
- Make hormones like oestrogen, testosterone and adrenal hormones.
- Help your metabolism work efficiently; eg cholesterol is essential for your body to produce vitamin D.
- Produce bile acids, which help the body digest fat and absorb important nutrients.
- Low levels of cholesterol are associated with depression, suicide and, in older women, lung cancer.
The big Cholesterol Myth
Cholesterol for many years now has been reduced to a single figure – a number that is said to indicate health or disease, high cholesterol is said to be bad, low cholesterol is said to be good. Eventually this was broken down into two forms of cholesterol that you needed to know about, two numbers to indicate health – HDL (called the “good cholesterol”) and LDL (called the “bad cholesterol”).
It has become clear with consistent research that your cholesterol number is irrelevant; it is not an accurate way to determine one’s health including risk of cardiovascular disease. LDL’s and HDL’s can both be good and bad, depending on whether they have been oxidised and depending on whether important inflammatory markers are high in the blood (eg C-reactive protein (hsCRP), triglycerides, ESR and Lp(a). If you are overweight, especially if carrying visceral fat (the abdominal fat that covers your organs), you can be sure that you have oxidised cholesterol regardless of if you have a “good number”. Visceral fat releases toxins into the body causing inflammation and disease. The other very important numbers are your glucose and insulin levels, if they are high that drives inflammation and increased triglycerides.
Did you know that you make adrenal hormones such as cortisol when you are stressed? These hormones are made from cholesterol so stress causes your liver to make more cholesterol!
The body uses cholesterol to repair damage to the arteries caused by inflammation; these fatty deposits that develop in the arteries are your body’s short term solution to seal up the damage (kind of like a bandaid in your arteries). If the reasons for the inflammation are not addressed this will eventually cause the vessels to narrow and they can eventually become blocked. This can lead to heart attack or stroke.
Sources of cholesterol
There are two sources of cholesterol in the body. Some is present in foods (eg dairy products and meats), but most is made by the liver. Foods from plants do not contain cholesterol. You may be surprised to learn that eating foods that contain fat is not what causes heart disease. That’s right, eating cholesterol does not cause heart disease! For a long time saturated fat has taken the blame for a more complex issue.
The story continues in part 2
For more information or personalised advice on a healthy diet contact Informed Health on (02) 47 222 111 or www.informedhealth.com.au
References and further reading:
Dreon DM, Fernstrom HA, et al. Low-density lipoprotein subclass patterns and lipoprotein response to a reduced fat diet in men. FASEB Journal, 1994. Available at URL: http://www.ncbi.nlm.nih.gov/pubmed/8299884
Dreon DM, Fernstrom HA, et al. Change in dietary saturated fat intake is correlated with change in mass of large low-density-lipoprotein particles in men, The American Journal of Clinical Nutrition, 1998. Available at URL: http://ajcn.nutrition.org/content/67/5/828.short
Eddey Stephen. Cardiovascular Disease: The best treatment options, 2011. Health Schools Australia, Gold Coast, QLD, Australia.
Mensink RP, Katan MB. Effect of dietary fatty acids on serum lipids ad lipoproteins. A meta analysis of 27 trials. Arteriosclerosis and Thrombosis, 1992. Available at URL: http://www.ncbi.nlm.nih.gov/pubmed/1386252
Mensink RP, Zock PL, et al. Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials, The American Journal of Clinical Nutrition, 2003. Available at URL: http://ajcn.nutrition.org/content/77/5/1146.short
Ravnskov U. The questionable role of saturated and polyunsaturated fatty acids in cardiovascular disease, Journal of Clinical Epidemiology, 1998. Available at URL: http://www.ncbi.nlm.nih.gov/pubmed/9635993
Other references and studies are available here: http://www.dietdoctor.com/science
Big Fat Lies (a brief video history of the failed fat/lipid hypothesis approx. 2 ½ minutes): http://www.youtube.com/watch?v=v8WA5wcaHp4