WHAT IS THE EVIDENCE?
We do know that the EPIC Norfolk paper concluded that ‘Glycated haemoglobin concentration seems to explain most of the excess mortality risk of diabetes in men and to be a continuous risk factor through the whole population distribution.’ It is therefore desirable to try to achieve near normoglycaemia in Type 1 Diabetes if at all possible. http://www.bmj.com/content/322/7277/15?ijkey=34136a7ae31af9ef58502ca8a32324070317d353&keytype2=tf_ipsecsha
Unfortunately, this ambitious target received a setback after reporting of the Accord Trial, which attempted to treat participants with type 2 diabetes to normal levels but did not demonstrate any improvement of cardiovascular outcomes and worryingly an increase in mortality. https://www.nhlbi.nih.gov/news/press-releases/2008/accord-clinical-trial-publishes-results
One reason for this could have been the carbohydrate content of the diet (55%), which would have increased the plasma insulin levels and hence systemic inflammation.
An important trial was published in 2012, looking at the potential to lower blood glucose safely to improve glycaemic control in Type 1 Diabetes. It concluded that:
.An educational program involving a low-carbohydrate diet and correspondingly reduced insulin doses for informed individuals with Type 1 Diabetes gives acceptable adherence after four years. One in two people attending the education achieves a long-term significant HbA1c reduction.
This was a trial in Sweden, which reported a significant reduction of 1.3% (7.7-6.4%)(61-46mmol/mol) in HbA1c with adherent persons in the experiment (48%). The normalisation of blood glucose was immediate on day 1 of the trial. https://dmsjournal.biomedcentral.com/articles/10.1186/1758-5996-4-23
In another trial by the same author reporting of severe hypoglycaemic episodes reduced from 2.9 per week to 0.5 per week after one year in participants on a relatively modest carbohydrate intake of 70-90g per day (current guideline 250- 300g/day). Daily bolus insulin doses reduced from 21.1 units per day to 12.4 units per day at 12 months. https://www.ncbi.nlm.nih.gov/pubmed/16454166
A short study by Krebs reported similar results on HbA1c reduction for low carbohydrate diets in Type 1 Diabetes. They also reported that there was no detrimental effect on lipid profiles. The study was very short, just three weeks, but anecdotally people with T1 using a low carbohydrate diet report either no change or favourable change in lipid profiles. Data obtained from this Type 1 Program will shed more light on this area. https://www.ncbi.nlm.nih.gov/pubmed/26965765
Carbohydrate restriction diets compare well with the DAFNE trial. DAFNE teaches insulin management around the currently recommended conventional food. In the DAFNE trial, there was a reduction of HbA1c of only 0.36% (4 mmol/ mol) at four years.
The REPOSE Trial combining DAFNE with intensive insulin management using a conventional diet reported an HbA1c reduction of 0.85%-0.42% at two years (multiple injections v’s pumps in those with T1 with a similar starting HbA1c to the Swedish trials mentioned earlier). Analysis of the data from the REPOSE trial shows that a tiny 3% of those participants achieved the NICE guideline target of 48mmol/mol (6.5%). http://www.bmj.com/content/356/bmj.j1285
Compare this with data from the Facebook community, Type1grit where almost the exact opposite percentage achieve or commonly exceed the
NICE guideline target. Type 1Grit responders using a diet averaging 35g of carbohydrate had a mean daily carbohydrate intake of 36 g. The reported mean HbA1c was 5.67% ± 0.66%. http://www.thejournalofdiabetesnursing.co.uk/media/content/_master/3071/files/pdf/jdn16-9-364-9.pdf
Improving glycaemic control reduces not only physical complications but also mental health measures, which are equally, if not more important, to the individual concerned. Depression is more common in diabetes but improved glycaemic control, and indeed, a sense of being in control makes a significant difference in Type 1 Diabetes (Bernstein University Module 42-YouTube).
To back this up, a study from the University of Illinois on young adults found that as fear of hypoglycaemia and fear of complications increase, quality of life decreases, and as self-efficacy, or the person’s belief in themselves to achieve goals and positive outcomes increases, so does the quality of life.
Quality of life was not associated with either diabetes self-management behaviours or diabetes knowledge. Thus, fear of hypoglycaemia, fear of complications, and self-efficacy may be appropriate primary outcomes to use in interventions designed to improve the quality of life in young adults. https://www.ncbi.nlm.nih.gov/pubmed/26628250
One person with Type 1 put it like this; ‘a sense of personal pride comes about when a patient takes control of their own health, they then will be more likely to seek out other positive health behaviours, and to pass on the experience to others as their confidence improves. Personally, I believe part of the problem in healthcare surrounds the deferral of responsibility to the HCP. I look back on my own experience of this in T1D management as having been nothing short of disastrous’.
Health Care Professionals will have the opportunity through collaboration to guide their Type 1 patients towards achieving their own goals but also towards fulfilling the recognised biological measurements that are known to reduce complications. This is important because it has been shown that a reduction in HbA1c and a positive change in hope is associated with an increased frequency of monitoring in young people.
The latest NICE guideline for adults with Type 1 Diabetes NG17 recommends a target HbA1c of 48mmol/mol or lower. This is pragmatic figure worked around a compromise between the frequency of complications and hypos. This guideline also expressly excluded diets involving carbohydrate restriction with no explanation for why. This can be found in Appendix C section 1.2.2 p46. https://www.nice.org.uk/guidance/ng17/evidence/appendices-af-pdf-435400238
However, there is good evidence, provided above, that carbohydrate-restricted diet is a safe and effective strategy in Type 1 Diabetes, and there is also a wealth of anecdotal evidence involving thousands of individuals with Type 1 Diabetes using low carbohydrate diets. It is becoming increasingly recognised that daily glycaemic variability might be worse than even constant high glucose. Ketogenic diets smooth out peaks and troughs of blood glucose and also can maintain near normoglycemic levels.