Could Artificial Sweeteners Cause Weight GAIN?

While artificial sweeteners have previously been touted as an excellent way to replace sugar in your diet and help with weight loss, they have in recent years been found to impact our biology in ways that may have adverse effects on our metabolism.  Rather than helping in a quest for weight loss, is it possible that sweeteners could actually cause weight gain and metabolic disease?

A recent systematic review and meta-analysis was recently published in the Canadian Medical Association Journal, which collected the currently available evidence to try to answer this question and received worldwide attention in doing so.  They included 37 trials (including 7 randomized controlled trials and 30 cohort studies), looking at a total of over 400,000 individuals (about 1,000 of whom were in the randomized studies).

In their analysis of the randomized controlled trials, over a median follow up of 6 months, they found no significant effect on body mass index (BMI) or measures of body composition.  So, use of sweeteners did not result in weight loss, but there was no weight gain seen either.

In the cohort studies, over a median follow up of 10 years, they found an increase in weight, BMI, and waist circumference, and a higher incidence of obesity, metabolic syndrome, type 2 diabetes, high blood pressure, stroke, and cardiovascular events.

So overall, none of the evidence assessed showed a benefit to weight, and the observational data suggested adverse effects of sweeteners on weight and health - none of which is good news.  And why is there a difference in conclusions between the randomized trials versus the observational (cohort) data?

Well, it's possible that the randomized trials were not long enough or big enough to show a negative impact on health, and that if they had been longer trials, perhaps results would have been different.

On the other hand, observational (cohort) data does not give us as trustworthy of an answer to any research question, because the results can be muddied by other factors. One concern is that these data may be confounded by 'reverse causation' - meaning that people with obesity, or those more prone to develop obesity (eg family history of obesity) are more likely to use sweeteners to help manage their weight (rather than the sweeteners being the cause of weight gain).

Either way, there is research to suggest biological mechanisms by which sweeteners could have an adverse impact on our metabolic health, particularly in relation to changes they induce in our gut bacteria, as well as our neurobiological response to these chemicals.  Further research is clearly needed to better understand their effect on our health.

Remember also that there is no doubt that excess sugar consumption is associated with weight gain and all of the above metabolic complications - so swapping sugar back in is not the answer either.

Follow me on twitter! @drsuepedersen

www.drsue.ca © 2017

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Testing Blood Sugar - Is There A Point?

In the management of people with diabetes, we routinely equip patients with glucose meters and ask them to check sugars at home.  While the importance and utility of checking sugars at home for people using insulin is clear, there is much debate about whether this is useful for people with type 2 diabetes who are not on insulin.  A recent study, which got a lot of media hype, tackled this question.

The study, published in JAMA Internal Medicine, randomized 450 people with type 2 diabetes and not using insulin, to either a) no home glucose montoring; b) checking sugars once daily; or c) checking sugars once daily plus automated educational/motivational messages delivered to the patient from the meter.

The researchers found that there was no difference in diabetes control (A1C) nor health related quality of life after 1 year, and concluded that glucose monitoring in people with non-insulin-treated type 2 diabetes should not be routine.

I have some major beefs with this conclusion:

1.   Testing once a day does not tell a person very much about their blood sugar.   In order for home testing to be useful, I advise 'paired meal testing': checking before a meal, and checking again 2 hours later.  This can be very helpful to see how certain types of food affect your blood sugar, and can be help to eat mindfully and manage portion control.  I don't necessarily advise doing this every day: checking each of breakfast, lunch, and dinner once per week can be enough.  However, depending on what kind of medication a person is taking, I may recommend more often.  Also, if diabetes control is not great, then checks (in my opinion) should be done more frequently so that we can figure out how to bring down the sugars effectively and safely.

2.  As the authors note, the study was not powered to determine if there are benefits to checking sugars around the time of medication or dose changes.  It is very difficult for a doctor to know what the next best medication may be without knowing the pattern of blood sugars through the day.  Knowing the pattern of blood sugars is extremely important when new medications are added onto sulfonylureas and insulin in particular, because these medications can cause low blood sugar.  For example, if sugars are highest in the morning and lower later in the day, there is a risk of causing low sugars if a treatment is added that brings down sugars in the morning (as sugars later in the day will go down too).

3.  Compliance with sugar checks in the study was poor by one year, declining gradually over the year, with only about 55% of people in the monitoring groups checking sugars each day by the 1 year mark.  Interestingly, the diabetes control (A1C) was better at 3, 6, and 9 months in the glucose monitoring groups, compared to those not monitoring - perhaps the lack of difference in A1C by 1 year was due to the poor compliance with glucose checks by that point in time.

4.  The study team did not engage with patients after their baseline visit - meaning patients were on their own to interpret their blood sugars without help from the study team.  Their family doctors received a copy of blood sugar results, but the study did not collect info on what was done with that data, and these clinicians had minimal interaction with the study team.  

Diabetes is a team sport - an important part of the benefit of checking blood sugars is to discuss these results with your health care team for help in optimizing control.  While the setup of this study was intended to be 'real world', I would submit that what patients perceived as their 'health care team' during the study (their usual doctors plus study investigators) were not working as a team and this may have limited the best possible use of home glucose monitoring.  And perhaps compliance with checking sugars in the study would have been better if that team was working together and more engaged with the patients, as is the ideal model of care.  We are blessed in Canada to be able to say that for most people in our country, the 'real world' does consist of free access to a team to help each individual with their diabetes care.

5.  For any patient on a sulfonylurea (and of course insulin), sugars must be checked before driving.   For a paper to conclude that glucose monitoring should not be routine (in a study where 36% of patients were on sulfonylurea!) is inappropriate.

Unfortunately, the media took hold of this study and has been shouting from the rooftops that people with non-insulin-requiring diabetes do not need to check their blood sugar.    I would be most saddened if patients get the message that they should stop testing their blood sugars, and would strongly advise people to continue to follow their doctor or diabetes educator's recommendations on how frequent of sugar checks is appropriate.

I hope this blog helps to provide some balance and perspective on what I feel is a study full of limitations.

Disclaimer: I have received speaking honoraria from makers of glucose meters.

Follow me on twitter! @drsuepedersen

www.drsue.ca © 2017

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