‘A diet with refined carbohydrate as the main source of calories is responsible for the epidemics in obesity, diabetes, heart disease and cancer.’
It is widely accepted that sugar is bad for your health, contributing to obesity and heart disease. The damage that regular consumption of other types of carbohydrate cause is not so widely recognised. A diet with refined carbohydrate as the main source of calories is responsible for the epidemics in obesity, diabetes, heart disease and cancer and may cause neuro-degenerative disorders like Parkinson’s disease and Alzheimers.
The persistent high blood sugar of a carbohydrate based diet contributes to chronic inflammation.
This leads to thickening of the blood vessel walls which reduces the internal volume of the vessel and increases blood pressure. This increases physical abrasion to the endothelium which attracts platelets and can lead to blockages in the circulation and rupture of the vessels. These are the main cause of strokes, heart attacks and haemorrhage.
The majority of tumors have an absolute requirement for glucose. Their growth may be restricted, however, with a low carbohydrate diet increasing ones chances of survival/remission (source). Spectacular results in brain cancer remission of mice on low carbohydrate (ketogenic) diets from studies in 2003 has led to dietary trials with human brain cancer patients and the results are very promising.
High blood sugar also results in persistent high blood insulin which leads to excessive deposition of body fat and the development of Type 2 Diabetes.
Nutritional properties of fructose
All sugars are not equivalent to glucose in terms of energy release or fat accumulation, and humans have a limited capacity to deal with high intakes of fructose. Dietary fructose enters the liver and interferes with the normal process of blood sugar control by glucose. It is rapidly metabolised to glucose precursors but more importantly to fatty acid and triglyceride precursors, ultimately leading to insulin resistance and obesity. The health outcomes from excessive fructose consumption are summarised below:
- Interference with the control of energy metabolism in the liver.
- It is converted to glucose in the liver but does not stimulate insulin synthesis in the pancreas, leading to:
- A reduction in leptin synthesis and loss of appetite suppression.
- It provides substrates for a massive increase in fatty acid and TG synthesis in the liver. This in turn leads to:
- Increased liver and serum TG, liver enlargement and hepatic steatosis (fatty liver), and overproduction of VLDL particles. This metabolic state culminates in:
- Metabolic syndrome and finally Type 2 diabetes.
- Stimulation of TG synthesis also leads to lipid peroxidation and general oxidative stress which can initiate cancers and CVD.
- Recent research has shown that fructose also accelerates cancer cell division by stimulating DNA synthesis.
The above list supports the warning to avoid all drinks and processed foods containing HFCS.
Dietary fibre and resistant starch: a re-evaluation
Research over the past 20 years has revealed some important differences in the roles of insoluble and soluble dietary fibres. Insoluble fibres such as cellulose and lignans play an important role in maintaining faecal bulk and intestinal health. Soluble fibres have a more important metabolic role. They are found in fruit, vegetables and cereals as pectins, gums, mucilages, hemicelluloses and resistant starch (RS). The metabolism of these soluble fibres is known to control blood glucose and cholesterol levels. Resistant starch is the most important member of the group, and its concentration in foods can be increased by cooking and processing. Like the other soluble dietary fibres, RS is fermented in the colon to provide long-term energy. It does not evoke an insulin response and is referred to as non-glycaemic carbohydrate. RS is a crucial dietary component for weight and blood glucose management and intestinal health.
Traditional diets rich in whole grains, vegetables and fibre have long been known to protect against obesity, diabetes Type 2, and several cancers. The major protective component in these diets, and often lacking in Western diets, is resistant starch. This is classed as the plant starch fraction that escapes digestion in the small intestine and passes into the colon. There it is slowly fermented by the resident bacteria to produce butyric acid which the main energy source for the cells of the colonic epithelium, the colonocytes. This production of butyrate protects against colon cancer, and helps to control blood glucose levels.
Dietary recommendations for RS
RS consumption in the developed world is calculated at 3–7g/day. The WHO recommends a total dietary fibre (soluble + insoluble) intake of >25g/day, whereas the CSIRO in Australia recommend 20g/day of resistant starch for optimum bowel health. Some clinicians and nutrititionists are now suggesting a daily intake of 25g for women and 40g for men for optimum health benefits since a high intake of RS appears to have no unwanted side effects. Green bananas and Basmati rice are a cheap and readily available source of RS.
The unique dietary properties of RS
- Gives some of the benefits of insoluble fibres as well as multiple benefits of soluble fibres.
- Improves the glycaemic response by increasing insulin sensitivity.
- Reduces obesity by stimulating fat oxidation.
- Reduces the inflammatory response.
- Helps to establish a healthy large bowel microflora.
- Reduces the risk of colon cancer by generating butyrate in the large bowel.
- Pure RS is gluten free and can replace flour in wheat-free and coeliac diets.
- Lowers the calorie content of foods by 50% when replacing refined flour or sugars.
- The physical properties of RS allow it to be incorporated into normal foods like bread, pastries, cakes, biscuits and drinks without causing consumer rejection.
- Reduces hunger pangs for two to three hours in the short term and 20–24 hours in the longer term.
- Helps to maintain bowel regularity by increasing microbial activity in the large intestine, to cause a mild laxative effect.
The facts listed above reveal how important resistant starch is as a crucial component of a healthy diet.
A Healthy Non-Sugar Sweetener- Xylitol.
Recent research is showing that many of the routinely used sweetners such as saccharin, sucralose, cyclamate and aspartame have unwanted and even toxic side affects.
The sugar alcohol xylitol is a popular commercial sugar replacement. It is a natural 5 carbon sugar alcohol found in cauliflower, raspberries and birch trees. The human body makes about 15g per day. It has no aftertaste and a sweetness equivalent to sucrose, but a very low glycaemic index of 7.0 (glucose Gi = 100), making it an ideal sweetener for diabetic and calorie-controlled diets. It is not fermented by oral bacteria that form plaque and cause tooth decay. It has additional health benefits, particularly for childen by inhibiting the growth of haemolytic streptococci and Streptococcus pneumoniae in the nasal cavity and protecting against otitis media. Only 30% is absorbed and metabolised in the liver without the involvement of insulin. The remainder passes into the large intestine where the resident microflora convert it to short chain fatty acids which are either absorbed and metabolised by the body or serve as a specific energy source for the colonic epithelium. Short chain fatty acids are known to protect against colon cancer. Consumption of xylitol is self regulating. Because it is poorly absorbed over-consumption leads to a build up of osmotic pressure in the gut . Water is absorbed from the surrounding tissues and diarrhoea ensues with only minor and temporary discomfort. Xylitol provides about 40% of the calories from an equivalent weight of sucrose. Currently xylitol retails on the internet in the UK at £8-£10 per kilo.
Health benefits of another sugar alcohol sweetener erythritol
The 4 carbon sugar alcohol erythritol is less sweet than xylitol being only 70% as sweet as sucrose. Unlike xylitol it is absorbed in the small intestine and excreted largely unchanged in the urine. This means that it causes less dietary upset than xylitol and also does not affect blood sugar levels . There is limited evidence that erythritol may act as an antioxidant and could protect blood vessel cell walls. Erythritol is now thought to be superior to xylitol for the prevention of tooth decay and growth of disease causing bacteria in the mouth, throat and nasal cavity. It is more expensive than xylitol and retails at about £18 per kilo.
Both xylitol and erythritol have been cleared for human consumption in relatively small doses and should be used in moderation.