Diabetes and coeliac disease

Here we focus on the main dietary considerations for patients with diabetes and coeliac diseaseA condition where a person is unable to eat gluten as it makes their body attack itself. .

Energy balance and body weight

• For those who are overweight (BMI more than 25kg/m2), caloric intake should be reduced and energy expenditure increased so BMI moves towards the healthy range.
• Prevention of weight regain is important once weight loss has been achieved. Those patients who are unable to lose weight should be strongly encouraged to prevent further weight gain.
• Diabetic patients have a high proportion of intra-abdominal fat and associated increased health risks related to insulin resistance and associated dyslipidemia and hypertension. Waist circumference is an important tool for assessing risk and monitoring progress.
• Even a modest weight loss of under ten per cent body weight improves insulin sensitivity, in addition to other health parameters, and should be set as an initial goal for patients needing to lose weight.

Protein

• In patients with no evidence of nephropathy, protein intake may provide ten to twenty per cent of total energy.
• In patients with Type 1 diabetes and evidence of established nephropathy, protein intakes should be at the lower end of the acceptable range (0.8g/kg normal body weight/day).
• Patients with diabetes, especially when poorly controlled or on haemodialysis, have increased protein turnover and their protein requirements may be greater than the recommended daily allowances. Protein intake should not be reduced below 0.6g/kg body weight/day.

Dietary fat

• Saturated and trans fatty acids should provide less than ten per cent total daily energy. A lower intake may be beneficial if LDL-cholesterol is elevated.
• Monounsaturated fats may provide up to twenty per cent total energy, provided total fat intake does not contribute more than thirty five per cent total energy.
• Consumption of two to three servings of fish (preferably oily fish) each week will ensure an adequate intake of n-3 fatty acids. Plant sources of n-3 fatty acids include soya oil, walnuts, linseeds, and some green leafy vegetables.

Carbohydrate

• The recommended range of carbohydrate intake (forty five to sixty per cent total energy) is based on the limits for total fat and protein intakes.
• The consumption of carbohydrates with a low glycaemic index (GI) and high fibre content should be emphasised. Following a gluten-freeWhen a food has less than 20 parts per million (ppm) of gluten so it is safe for people with coeliac disease to eat. diet can result in the elimination of fibre-containing cereal products and reduce fibre intake. The intake of foods such as pulses should be encouraged, both due to their high fibre content and low GI value.
• Most dietitians use a combination of methods when advising patients how to regulate their carbohydrate consumption, for example, qualitative advice based on the plate model; carbohydrate counting (with frequent glucose monitoring the insulin dependent patient can vary the amount of carbohydrate consumed or the time at which carbohydrates are eaten by adjusting insulin doses), 'exchanges', and the GI. Different approaches are required for different patients and in different circumstances.
• Carbohydrate counting gives greater dietary flexibility, while minimising the frequency of hypoglycaemia and peaks in blood glucose concentration, but requires intensive and time consuming assessment and teaching by experienced and highly trained staff.
• The GI is a useful way of quantifying the glycaemic effect of different carbohydrate foods. It is well-established that dietary sucrose does not increase blood sugars more than the same amount of starch. It should be emphasised to patients that when mixing foods together the GI changes, so mixing a low GI food with a high GI food becomes a medium GI meal. The GI should therefore not be used as a tool in isolation (2).
• For those patients with persistently raised triglyceride levels a carbohydrate intake at the lower end of the recommended range may be suggested.

Alcohol

• Advice given to the general population about sensible drinking (maximum of 14 units per week for women and 21 units for men, with one to two alcohol-free days per week, avoidance during pregnancy and by those with gastritis, pancreatitis, severe liver disease) also applies to those with diabetes.
• Alcohol intake should be restricted in those patients who are trying to lose weight or who have significant hypertriglyceridemia or hypertension.
• When alcohol is taken by those on insulin it is most appropriately consumed with a carbohydrate-containing meal, because of the risk of hypoglycaemia. Delayed hypoglycaemia may occur up to 16 hours after drinking. The hypoglycaemic effect of alcohol is far less likely to occur in patients taking oral hypoglycaemic agents such as Metformin.

Dietary management of patients with coeliac disease and diabetes

• Blood glucose levels should be monitored closely following coeliac disease diagnosis as insulin levels often need to be altered due to the increased absorption of carbohydrate.
• GlutenA protein that is found in the cereals wheat, barley and rye. -free alternatives to wheat-containing bread, pasta, biscuits and flour have approximately the same GI as their gluten-containing counter-parts, and therefore should not necessarily compromise the diet in terms of the GI (3).
• Naturally gluten-free carbohydrate foods with low GI values such as pulses, legumes, buckwheat, rice, sweet potato, oats*, mung bean noodles, sweet corn and fruit should be encouraged. 
• Dietary intervention needs to take into account increased requirements for calcium to promote good bone health. It is recommended that adults with coeliac disease have between 1000 milligrams (mg) and 1500mg of calcium each day.  This is based on the British Society of Gastroenterology (BSGBritish Society of Gastroenterology - an organisation focused on the promotion of gastroenterology within the United Kingdom, with a membership drawn from physicians, surgeons, pathologists, radiologists, scientists, nurses, dietitians, and others interested in the field. The BSG is a registered charity.), guidelines for osteoporosisA condition where your bones lose bone mass and become brittle. in inflammatory bowel disease and coeliac disease (2007) (4), and the recent review document from the BSG on the management of adults with coeliac disease (2010) (5).

* Oats can be tolerated by the majority of people with coeliac disease but most oats are contaminated. Therefore a gluten-free source must be used.

References

1. Nutrition Subcommittee of the Diabetes Care Advisory Committee of Diabetes UK. (2003) The implementation of nutritional advice for people with diabetes.  Diabetic Medicine 20:786-807. 

2. Mann JI, De Leeuw I, Hermansen K, Karamanos B, Karlstrom B, Katsilambros N, Riccardi G, Rivellese A, Rizkalla S, Slama G. (2004). Evidence-based nutritional approaches to the treatment and prevention of diabetes mellitus. Nutrition Metabolism and Cardiovascular Disease14:373-394. 

3. Packer SC, Dornhorst , Frost GS. (2000). The glycaemic index of a range of gluten-free foods.  Diabetic Medicine 17(9):657-60.

4. Lewis NR, Scott BB for the British Society of Gastroenterology (2007) Guidelines for osteoporosis in coeliac disease and inflammatory bowel disease.  Accessed at www.bsg.org.uk

5. British Society of Gastroenterology (2010) The management of adults with coeliac disease. Accessed at www.bsg.org.uk