Welcome back:
This week I am presenting 2 posts from the UK. Dr John Briffa (www.Drbriffa.com) is one of the few medicos on-line that are wroth following and I thought that these 2 posts of his are well worth passing on for you to read.
Enjoy.
Low-carbohydrate diets look good for the prevention and treatment of cancer
Posted on 29 November 2011
In general terms, I recommend a diet lower in carbohydrate than conventional guidelines say is healthy. At least part of my thinking is based on abundant evidence linking a relatively carbohydrate controlled diet with benefits in terms of body weight and disease markers for conditions such as heart disease and type 2 diabetes. However, I came across a recent paper which made me think more about the impact a low-carbohydrate might have on risk of another important condition – cancer [1].
You can read a summary of the paper here and download a provisional pdf of the full paper here.
The paper starts with reference to hunter-gatherer diets, and their relatively protein-rich, low-carb nature, and remarks that cancer has been found to be rare in societies eating such a diet. It then goes on to postulate several major mechanisms that may account for this association. These include:
1. Cancer cells feed preferentially on sugar (glucose)
Glucose (from sugary and starchy foods) provides the prime fuel for cancer cells, so a diet lower in carbohydrate may therefore reduce tumour development or progression.
2. Insulin and IGF-1 can stimulate tumour cell growth
High carbohydrate diets increase levels of insulin and what is known as insulin-like growth factor-1 (IGF-1) which stimulate tumour cell growth. A lower carbohydrate diet may reduce tumour proliferation as a result.
3. Ketones suppress cancer
Very low carbohydrate diets can lead to the production of ‘ketones’ (mainly produced from fat) that suppress tumours.
4. Low-carbohydrate and ‘ketogenic’ diets ‘starve’ cancer
Low-carbohydrate diets mimic caloric restriction and ketogenic diets mimic starvation – and caloric restriction/starvation is linked to reduce tumour development and progression.
5. Low carbohydrate diets can reduce inflammation
Inflammation is believed to be a risk factor in the development of cancer, and high-carb diets encourage inflammation. Low-carbohydrate diets have been found to be more effective than low-fat ones in terms of reducing markers of inflammation.
The paper also makes the case that such diets may help better meet the nutritional needs of those with cancer.
I’ve only plucked out some of the highlights of this paper, as you can read it in its entirety if you so wish. If you do, though, you may well find that the paper makes a pretty compelling case for the role of carbohydrate-restricted diets in the prevention and treatment of cancer.
References:
1. Klement RJ, et al. Is there a role for carbohydrate restriction in the treatment and prevention of cancer? Nutrition & Metabolism 2011, 8:75
Questions raised over the role of HDL-cholesterol in cardiovascular disease
Posted on 2 December 2011
Cholesterol in the bloodstream is transported in two main forms: ‘low-density lipoprotein-cholesterol’ (LDL-cholesterol) and ‘high-density lipoprotein-cholesterol’ (HDL-cholesterol). Conventional wisdom tells us that LDL-cholesterol is responsible for the fatty build-up on the inside of arteries known as ‘atherosclerotic plaque’, but that HDL-cholesterol clears this plaque. Because of this, HDL- and LDL-cholesterols are dubbed ‘good’ and ‘bad’ cholesterol respectively.
A paper was published recently which attempted to explore further the relationship between HDL-cholesterol and risk of cardiovascular disease. Low levels of HDL-cholesterol have been associated with enhanced risk. But just because two things are associated with each other, does not mean one is causing the other.
Low HDL-cholesterol levels often go hand-in-hand with other metabolic ‘abnormalities’ including raised triglyceride (a form of blood fat) levels, raised blood pressure, raised blood sugar levels and abdominal obesity. Could it be one or more of these associated factors or other factors entirely that account for the relationship between low HDL-cholesterol levels and heightened risk of cardiovascular disease.
To answer this question, Danish scientists isolated individuals with low HDL-cholesterol levels as a result of a genetic glitch [1]. In these individuals, HDL-cholesterol levels are low, but this is usually in isolation and not in combination with other metabolic abnormalities (such as raised triglycerides, blood pressure, blood sugar and abdominal obesity).
It turns out that in these individuals with genetically determined low HDL-cholesterol levels, risk of heart attack is no higher than in the general population. The logical conclusion here is that low HDL-cholesterol does not cause heart attacks (which means that higher levels do not protect against it either). In other words, this evidence strongly suggests the link between HDL-cholesterol levels and cardiovascular disease risk is only an association and not causal.
But if this is the case, could the same not be true for LDL-cholesterol too?
Many doctors and scientists will not hear of such a thing, of course, and will quote studies which show cholesterol-reduction with statin drugs reduces risk of cardiovascular disease as evidence of the fact LDL-cholesterol causes heart disease. However, as is well-recognised now, statins have many actions in the body which might reduce cardiovascular disease risk in a way which has nothing to do with cholesterol (including anti-inflammatory and blood-thinning properties).
Also, we have evidence that statins substantially reduce the risk of stroke, even though cholesterol is a weak or non-existent risk factor for stroke. And we have evidence that statins reduce the risk of cardiovascular disease in individuals with normal or even low levels of cholesterol. These lines of evidence suggest that statins actually work through mechanisms that are distinct from their cholesterol-reducing properties.
I know that some will tell us that cholesterol is to be found in atherosclerotic plaque and that ‘proves’ that cholesterol causes cardiovascular disease. Actually, though, it does nothing of the sort. If I graze my knee and form a scab there, chemical analysis of the scab will reveal something called fibrin (a clotting agent). Has fibrin caused my scab? Of course not.
References:
1. Haase CL, et al. LCAT, HDL Cholesterol and Ischemic Cardiovascular Disease: A Mendelian Randomization Study of HDL Cholesterol in 54,500 Individuals. The Journal of Clinical Endocrinology & Metabolism November 16, 2011
See you next week when I’ll be looking at 4 fat loss proptocols to follow when you want to drop fat fast!!
Be well.