LOW CARBOHYDRATE IN TYPE 1 DIABETES: PRACTICAL ASPECTS OF MANAGEMENT
The beauty of the carbohydrate management approach is in its simplicity. The method is familiar to both clinicians and patients and has the usual three aspects:
- Basal insulin
- Carbohydrate counting
- Bolus insulin
- BASAL INSULIN
The basal dose that the patient is already taking is probably accurate but can be refined by periods of fasting. Most people nowadays would recommend twice-daily basal insulin split 50:50, even for the latest ultra-long-acting insulins. This method of fine-tuning basal dosing is explained in the core module.
- CARBOHYDRATE COUNTING AND BOLUS INSULIN
The bolus dosing principle is nearly the same as the person is already doing: count the carbs and inject insulin in the ratio that they have previously been taught in the clinic. On a very low carbohydrate diet, the blood glucose will start to normalise from day one, and because of the familiarity of the method, people with Type 1 Diabetes should take to it very quickly. The exchange between patient and clinician can be adapted to the individual’s needs and frequency of contact tailored to suit.
Protein ingestion should be considered at an early point. As the participant gets better at managing carbohydrates to a lower level, they will start to notice the effect of the protein, a slow rise in blood glucose at 2-3 hours due to glucose production, which is a metabolic consequence of dietary protein.
The protein plateau would have always been there but masked by the more substantial glucose-raising effect caused by the carbohydrate.
Modern rapid-acting insulins are designed for high carbohydrate diets and have a necessary rapid time of onset. When carbs are removed from the menu, it might be required to alter the timing of injection. Ultra-rapid insulin might necessitate doses during or even after a meal. Consider less aggressive insulin such as Actrapid or Humulin S. Some patients prefer this as it enables them to control their protein intake more effectively.
A rough guide is to count the grams of protein and inject about half of the usual ratio that has been worked out for carbohydrates, e.g., if the ratio of insulin to carbohydrate is 1 unit to 10g carbs, then it is 1 unit of insulin to 20g protein.
This is a good starting point and can be refined through the timing of the dose and amount as required for each individual.
- MANAGING INSULIN
Typically, a patient will find that they are injecting less insulin than before. If they have access to a continuous glucose meter, the learning may be faster.
We should be aiming for a situation where every T1 should at least be eligible for a CGM.
Patients are recommended to allow 5 hours between bolus insulin injections to allow the previous dose to be degraded. If not, it could be that the hypo risk increases due to insulin stacking.
It is inevitable that the daily doses of bolus insulin will drop. The basal insulin dose is likely to stay the same. There are reports online of people coming off insulin altogether. These are mostly people with type 2 misdiagnosed as insulin deficient. It is vital to reinforce to the patient that the object of this programme is solely to normalise glucose levels. The patient will almost certainly reduce their insulin doses but should not be given the impression that this diet is a cure.
Most people who have had diabetes for over a decade will have some insulin resistance as a result of the chronic over-injection of insulin required to manage the higher than needed amounts of carbohydrate in their diet. As the HbA1c normalises, some people find that they get more sensitive to their insulin and need to reduce the basal dose, this happens over months if at all. It is something to bear in mind. They also need to be aware that insulin sensitivity to bolus doses improves and they might find that the time to act of their basal insulin decreases
Once a person has learned to perfect their dose of basal insulin, some opt to skip meals, especially at times of day when diurnal insulin resistance is highest (most often breakfast when required bolus doses are usually higher most people). This can be used in some cases to improve glycaemic control, and this is a frequent topic on some low carb forums.
OTHER BENEFITS OF LOW CARBOHYDRATE IN TYPE 1 DIABETES
Reported beneficial effects of lowered carbohydrate in Type 1 are increased clarity of thought, improved visual acuity, a sense of energy, and a reduction in aches and pains. The latter is likely due to a decrease in the glycation of tissue. Age-Related Glycation End-products (AGEs) formed as a result of chronic hyperglycaemia can damage tissue function and promote inflammation. Glycation of tissues is not unique to erythrocytes (which are easy to access to measure HbA1c). But arranging an HbA1c blood test every three months can be very motivating
There can be an improvement in mood swings and also depression, especially in people who previously found control difficult with higher carbohydrate diets. It might be useful to measure wellbeing through a suitable scoring system such as Warwick Edinburgh or similar. Measurement of this at intervals throughout the year can also be insightful.