Low-carbohydrate diets and type 1 diabetes

By The Low Carb Clinic, 27 August 2019 - 1105 words (6 minutes)

Type 1 diabetes is a condition where the body is not able to produce any of the blood-sugar-lowering hormone, insulin. This happens because the cells that produce insulin – the beta cells, in the pancreas – have been destroyed.  

Insulin is an essential hormone – without any, you can die, very quickly. 

T1DM is normally managed with injections of insulin – a ‘background’ dose or long-acting insulin to maintain a healthy blood sugar through the day (as well as perform many other vital metabolic functions), and then extra doses of ‘fast-acting’ insulin with meals. But over time – just like in people with type 2 diabetes - people with type 1 diabetes can become insulin resistant, meaning they will require higher and higher doses of insulin. This is the sad reality of ‘double diabetes’ - T1DM (because the person cannot produce any insulin at all) and T2DM (where the person has become resistant to the effects of insulin – leading to high blood insulin levels and high blood sugar levels).  

This is why a low-carbohydrate diet can help. With fewer dietary carbohydrates, blood sugar does not rise as high, and so less insulin needs to be injected, in the first place. With fewer dietary carbohydrates and less injected insulin, there is less chance of developing insulin resistance - and so less chance of developing the many health problems that come along with it.  

What’s in a name? 

There are two types of diabetes – type 1 and type 2. In some ways, they are very different diseases – but they both relate to insulin and blood sugar level. 

 The full name for diabetes is diabetes mellitus: 

• Diabetes (Greek) means to siphon - ‘to pass through’  
• Mellitus (Latin) means ‘honeyed’ or sweet   

Together, they mean to ‘pass sweet urine’. Diabetes mellitus means there is sugar in the urine.   

In type I diabetes, the body cannot make any insulin, because the insulin-producing ‘beta cells’ have been destroyed. T1DM is an autoimmune disease – which means the immune system has attacked the body’s own cells, killing them. In type 1 diabetes, it is the beta cells that have been destroyed. T1DM often occurs very suddenly. Without any insulin, the blood sugar rises extremely high, extremely quickly. A person becomes very sick, very fast. 

In type 2 diabetes, the body no longer responds properly to insulin.  

Unlike in T1DM, in T2DM, there is lots of insulin around, but the cells are ‘resistant’ to its effects. In this way, T2DM is almost the opposite to T1DM – in one, there is no insulin, and in the other, there is lots of insulin (but the insulin is not able to do its job properly)... But the ‘hallmark symptom’ is the same.  

Whether there’s no insulin, or the cells aren't responding properly to insulin, the end result for both is that the blood sugar level will rise and rise. There is sugar in the blood, and then sugar in the urine – the person has ‘Diabetes Mellitus’.  

We don’t know what causes T1DM.  

There are about 2,500 new cases of T1DM each year - an average of 7 per day[1]. T1DM often comes on in childhood. Symptoms include sudden weight loss, fatigue, blurry vision, and extreme dehydration – most people are hospitalised. Managing type 1 diabetes can be difficult – it can take a lot of time, effort and learning (especially when parents are having to manage it in their young children). Standard treatment for T1DM involves injections of long and short acting insulin. Long acting or ‘basal’ insulin is like background insulin, keeping the body’s blood sugars relatively stable between meals.  

Short acting insulin is taken with meals. It is normally matched with the amount of carbohydrate in a meal since insulin’s main role is to manage excess blood sugar - which mostly comes from dietary carbohydrates. This might be called ‘carbohydrate counting’ - matching a dose of insulin with the amount of carbohydrate being eaten. It's a very intensive learning curve – inject too much insulin, and the person will have a ‘hypo’ (hypoglycemia, or low blood sugar), which can be fatal.  

Inject too little insulin, and all those carbohydrates cause high blood sugar (hyperglycemia). High blood glucose means advanced glycation end products will form in the blood – harmful compounds which damage every organ in the body: the heart, the eyes, the kidneys, the nerves, the toes. The constant mental and physical strain of managing these risks – hypo and hyper-glycemia – on quality of life, mood, energy, as well as general health and wellbeing cannot be overstated. T1DM is an extremely hard condition to manage when having to match the amount of carbohydrate with doses of insulin.  

Injecting insulin seems very logical since T1DM is a disease of no insulin. And it is important to take insulin – it’s required to survive. But dive a little deeper, and we can find two major problems with injecting insulin to match carbohydrate consumption (and fortunately, we also find a diet-based solution).  

Problem one: insulin toxicity  

At first, a small dose of insulin will be enough to keep blood sugar levels stable. But (just like in type 2 diabetes), a person with T1DM will soon also become resistant to the effects of insulin, and so require higher and higher doses over time. High insulin doses are linked to worse outcomes for patients with diabetes.  

The higher the insulin dose, the more likely the person is to gain weight – especially around the waist, which is the most harmful type of fat.  

High insulin is associated with high blood pressure[2], as well as hardening of the arteries around the heart (atherosclerosis)[3] and unhealthy cholesterol patterns[4]. Together, these are the symptoms of metabolic syndrome – a cluster of conditions that increase the risk of heart disease and stroke.  

Problem two: insulin leads to insulin resistance  

Not only does being resistant to insulin mean higher blood sugars (and so all of the diabetic complications that we were trying to avoid) – being insulin resistant also creates further weight gain, high blood pressure[5], gout[6], and cardiovascular disease[7].  

Insulin and insulin resistance, going around in circles and making each other (and the associated complications), worse – even for a person with T1DM, who began with no insulin at all[8]. In time, treating a person with T1DM with high doses of insulin means they develop ‘double diabetes'[9]. It’s the sad truth of treating T1DM with a high-carbohydrate diet, and so high doses of insulin. The person begins with the harmful effects of high blood sugars and no insulin at all (T1DM) and ends with the harmful effects of high insulin and insulin resistance (T2DM).  

A low-carbohydrate diet for T1DM: stopping the cycle  

Insulin helps shuttle excess blood glucose into cells. But on a low-carbohydrate diet, we are not adding so much extra glucose into our blood, so we simply don’t need as much injected insulin. High insulin is harmful to health. With fewer carbohydrates, we can use less insulin. With less insulin, we don’t have to ‘feed’ insulin with carbohydrates, preventing the risk of deadly ‘hypos’[10]. With less insulin, we’re less likely to develop insulin resistance. A low-carbohydrate diet stops the vicious cycle of high blood glucose, high blood insulin, and insulin resistance.  

You should consult a doctor before starting a low-carbohydrate diet if you have type 1 diabetes. Because a low-carbohydrate diet is so effective at reducing blood glucose and insulin resistance, doses of any insulin you take will need to be lowered.  

It is extremely important to know how to test your blood glucose and blood ketone levels, the effect of protein, carbohydrates and fat on your blood sugar, and how titrate your medication doses appropriately. 

References

1. Australian Institute for Health and Welfare. (2018, July 24). Retrieved from Australian Government: https://www.aihw.gov.au/reports/diabetes/diabetes-snapshot/contents/how-many-australians-have-diabetes/type-1-diabetes 
2. Modan, M., Halkin, H., Lusky, S., Almog, S., Eshkol, A., Shefi, M., . . . Fuchs, S. (1985). Hyperinsulinemia. A link between hypertension obesity and glucose intolerance. Journal of Clinical Investigation, 75(3), 809-817. 
3. Takahashi, F., Hasebe, N., Kawashima, E., & Takehara, N. (2006). Hyperinsulinemia is an independent predictor for complex atherosclerotic lesion of thoracic aorta in non-diabetic patients. Atherosclerosis, 187(2), 336-342. doi:https://doi.org/10.1016/j.atherosclerosis.2005.05.041 
4. Feinman, R., Pogozelski, W., Astrup, A., Bernstein, R., Fine, E., Westman, E., . . . Worm, N. (2015). Dietary carbohydrate restriction as the first approach in diabetes management: critical review and evidence base. Nutrition, 31, 1-13. 
5. Rayees, T., Sheikh, S., Dil, A., Irfan, Y., Azhara, G., Bashir, L., & Sawan, V. (2014). Role of insulin resistance in essential hypertension. Cardiovascular Endocrinology & Metabolism, 3(4). doi:10.1097/XCE.0000000000000032 
6. Gheita, T., El-Fishawy, H., Nasrallah, M., & Hussein, H. (2012). Insulin resistance and metabolic syndrome in primary gout: relation to punched‐out erosions. International Journal of Rheumatic Diseases, 15(6). Retrieved from https://doi.org/10.1111/1756-185X.12007 
7. Cleland, S. (2012). Cardiovascular risk in double diabetes mellitus--when two worlds collide. Nature reviews. Endocrinology., 10(8), 476-485. doi:10.1038/nrendo.2012.47
8. Cleland, S. (2012). Cardiovascular risk in double diabetes mellitus--when two worlds collide. Nature reviews. Endocrinology., 10(8), 476-485. doi:10.1038/nrendo.2012.47 
9. Cleland, S., Fisher, B., Colhoun, H., Sattar, N., & Petrie, J. (2013). Insulin resistance in type 1 diabetes: what is ‘double diabetes’ and what are the risks? Diabetologia, 56(7), 1462-1470. doi:10.1007/s00125-013-2904-2 
10. Feinman, R., Pogozelski, W., Astrup, A., Bernstein, R., Fine, E., Westman, E., . . . Worm, N. (2015). Dietary carbohydrate restriction as the first approach in diabetes management: critical review and evidence base. Nutrition, 31, 1-13.