How Does Breastfeeding Protect Against Obesity?

Breast is best, when women are able to breast feed – we know this without a doubt.  Infants who are breastfed enjoy a long list of health benefits, including a reduced risk of infections, autoimmune diseases, SIDS, leukemia, and more.

Breastfeeding reduces the risk of obesity as well – the available data on this suggests that there is a 15-30% reduction in adolescent and adult obesity rates if any breastfeeding occurred in infancy, compared with no breastfeeding.  With the reduction in obesity risk comes a 40% decreased risk of the child developing type 2 diabetes later in life as well.  

So, how does breastfeeding protect against developing obesity later in life?  Well, there are a number of hypotheses.  For one, when a baby is breastfeeding, the amount of milk s/he takes in is self regulated. Simply put: when they are full, they stop drinking.  When a baby is bottle fed, there may be a push for baby to finish the bottle  - possibly resulting in the baby taking in more food than s/he otherwise would have.  Thus, with breastfeeding, the baby’s brain is programmed to self regulate how much s/he wants to eat – programming that is likely carried on with them later in life.

Secondly, the gut bacteria that the baby develops may be influenced by whether the baby is breast or bottle fed.  We now know that the type of gut bacteria we carry can have a significant impact on the risk of obesity and metabolic disease such as diabetes.   Also, if a baby needs to take antibiotics, this can change the bacteria in his/her gut and may affect the risk of obesity.  Breastfed infants have a markedly lower risk of respiratory and gastrointestinal tract infection, portending a lower risk of needing antibiotics as well.

Thirdly, what the baby is being fed is of course different.  While every effort has been made to make infant formula as close to human milk as possible, there are many differences, with many factors unique to human milk that may affect nutritional status, energy balance and/or satiety.   

Still so much we need to research, learn, and understand about this fascinating area!

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Will Bariatric Surgery Help Me Control My Diabetes?

One of the major reasons why we might suggest bariatric (obesity) surgery to our patients with obesity and type 2 diabetes, is that studies have shown bariatric surgery to be very effective in improving diabetes control, or even putting diabetes into remission.  However, it has been slow to grow the body of research data in this area, as it is difficult to conduct high quality, long term studies in this field.

Now, just published, we have 5 year data showing that bariatric surgery (gastric bypass surgery and sleeve gastrectomy) are superior to medical therapy to treat type 2 diabetes in people with obesity.

I blogged on the 3 year data in this trial, called the STAMPEDE trial, when it came out in 2014 - where you can read about the structure, goals of the study and the results at that time.

Now, published in the New England Journal of Medicine, the extended results of the STAMPEDE study show that 5 years after bariatric surgery, 29% of patients who had gastric bypass surgery had tight control of their diabetes, vs 23% of those who had sleeve gastrectomy, vs only 5% of those who had intensive medical treatment alone.  A duration of diabetes of less than 8 years before surgery was the main predictor of achieving tight control of diabetes, suggesting that earlier intervention with bariatric surgery may give the maximum benefit in glycemic control.

There were also greater improvements in body weight, several measures of cholesterol, need for insulin, and quality of life in the surgical groups.  No late major surgical complications were reported except for one person in the sleeve gastrectomy group who underwent gastric bypass at year 4 to treat a gastric fistula.  Follow up at the 5 year mark was 90%, which is excellent.

While I still take issue to the target for diabetes control being too tight in this study at an A1C of 6.0%, this study does now give us good 5 year data to support that bariatric surgery can be an effective tool to help treat type 2 diabetes in people with obesity.

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Benefits of Continuous Glucose Monitoring With Insulin Injections in Type 1 Diabetes

In people with diabetes, continuous glucose monitoring (CGM) is an alternative to checking sugars with frequent finger pokes.  CGM is available as a stand alone tool, or can be integrated with an insulin pump system.  Most studies showing the benefits of CGM were done in people using insulin pumps.  Now, two studies show the benefits of CGM in people with type 1 diabetes using insulin injections to treat their diabetes.

The first study, published in JAMA, randomized 158 people with type 1 diabetes using insulin injections to use of either the usual form of self blood glucose monitoring (finger pokes) vs CGM.  At 6 months, the hemoglobin A1C (a marker of diabetes control) was 0.6% lower in the people using CGM compared to those using finger pokes.   People using finger pokes to check sugars during the study were also wearing a CGM during the study, but they could not access the readings on the CGM, with the purpose being for researchers to analyze what the CGM showed in the people using finger pokes during the study.  Importantly, this analysis found that people using CGM spent 37 minutes less per day with low blood sugar (43 minutes per day, compared to 80 minutes per day for people using finger pokes).

The second study, also published in JAMA, compared the effect of CGM vs finger poke monitoring in the same person, using a crossover design.  Patients were randomized to use either CGM or finger pokes for 6 months, then did the reverse for the next 6 months (with a 17 week break in between).  Amongst these 161 patients with type 1 diabetes, hemoglobin A1C was 0.43% lower during the time of CGM use, and they also reported less fear of hypoglycemia, greater well being and greater treatment satisfaction while using CGM. Patients were hypoglycemic 4.79% of the time while using finger pokes (using data from masked CGMs), vs 2.79% of the time with use of CGM.

One thing that I found particularly disturbing about these studies was the amount of time patients spent with low blood sugars.  While CGM improves upon this, we would ideally like patients with diabetes to have zero hypoglycemia.  CGM units have alarms that alert a patient when blood sugar is low, which can be lifesaving, especially for people who don't feel their low sugars and are at risk of sleeping through a low.  Hopefully improved glucose monitoring technology, as well as better insulins being developed, will help us to reduce lows further.  CGMs are unfortunately quite expensive, though some people are able to get the expense covered - talk to your insurance provider (if you have one) and/or your diabetes educator to find out about your options.

These studies clearly support the potential benefits of continuous glucose monitor (CGM) use in people with type 1 diabetes using insulin injections.

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New Class Of Cholesterol Medication Prevents Heart Attacks

Statin medications have long been the main class of medications that have been recommended to lower cholesterol, as they have been shown to be very powerful to reduce the risk of cardiovascular events.  Now, a new class of medications joins the ranks of statins: the PCSK9 inhibitor evolocumab (Repatha) has been shown to reduce cardiovascular events.

The top-line results of the study, called the FOURIER study, have now been released.  This was a study of 27,500 patients with cardiovascular disease who were already on optimized statin therapy, randomized to receive either evolocumab or placebo.  They found that evolocumab reduced the risk of their primary endpoint, which was the sum of cardiovascular death, non fatal heart attack, non fatal stroke, hospitalization for unstable angina, or coronary revascularization (angioplasty).

I am looking forward to learning more about the results of this trial and the amount by which risk was reduced - these data will be released in March at the American College of Cardiology meeting in Washington DC.  It will be interesting to compare these results to the results of the IMPROVE-IT trial, which showed that the combination of statin therapy with the cholesterol lowering medication ezetimibe lowered the risk of cardiovascular death, major coronary events, or non fatal stroke by 2.0 percentage points compared to statin therapy alone.

It is encouraging to see a new class of cholesterol medications being developed that reduce cardiovascular events.  There are many patients who do not tolerate statin therapy; perhaps the PCSK9 inhibitors may also reduce cardiovascular risk for them (studies on this are currently underway).  PCSK9 inhibitors are extremely expensive, which limits their use in clinical practice.  Perhaps with these data, guidelines will be revised and we may hopefully see more coverage options so that the benefits of PCSK9 inhibitors to reduce cardiovascular events can be more widely enjoyed.

Disclaimer: I have been involved in a clinical trial of PCSK9 inhibition. I have received honoraria as a medical education speaker and consultant from the makers of ezetimibe (Merck).

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Bariatric Surgery - Can We Predict Remission of Diabetes?

One of the most important benefits of bariatric surgery (especially gastric bypass and sleeve gastrectomy) is its ability to improve the control of type 2 diabetes, often to the point where type 2 diabetes actually goes into remission after surgery.  Not everyone with type 2 diabetes who has bariatric surgery will experience remission - about 70-80% of patients having gastric bypass and about 50-60% of patients having sleeve gastrectomy will experience remission.  Ideally, we would be able to predict the likelihood of diabetes remission before the surgery is done, as this is arguably one of the most important potential benefits of bariatric surgery.

A recent study tried to answer this question using a scoring system called the DiaRem Score, which looked at at 4 preoperative variables amongst a group of 407 patients who underwent gastric bypass surgery:

• age
• need for insulin 
• diabetes medication use (points assigned varied by type of medication)
• hemoglobin A1C (a blood test which is a 3 month report card of diabetes control)

They found that this score, which is based on the above 4 variables, was highly predictive of who went into remission from their type 2 diabetes and who did not.

Other scoring systems and variables have been looked at as well.  Other variables that stands out in the literature are a shorter duration of diabetes, and preoperative serum C peptide level, which is a marker of a person's ability to produce insulin.

It is exciting to know that as we learn more about bariatric surgery, that we can become better at predicting who may benefit from a diabetes standpoint.  However, a word of caution - longer term studies suggest that for people who do enjoy diabetes remission after bariatric surgery, the diabetes recurs in about 50% of these people by 5 years post op.  While there is still certainly a health benefit to being free of diabetes for a number of years, it is important to remember that the diabetes can return and must be screened for regularly and lifelong.

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Marijuana and Diabetes Risk - Friend or Foe?

In follow up to my blogs about the increased risk of diabetes associated with smoking (read more here), some of my colleagues have asked me to comment on whether there is also an increased risk of diabetes associated with marijuana use.  With the advent of medical marijuana, and the plans to legalize marijuana use in Canada, this is definitely an excellent question.

A question, which it turns out, we have very little data on which to base an answer.

One study examined body fat, insulin sensitivity, and various aspects of beta cell function (the pancreatic cells that make insulin) in 30 cannabis smokers, and compared them to people matched for age, gender, ethnicity, and body mass index. They found that cannabis smokers had a higher percentage of abdominal visceral fat (the fat around the organs that is the metabolically dangerous (diabetes inducing) fat).  Good cholesterol (HDL) was a little lower, and carbohydrate intake a little higher, but otherwise, there was not much difference between groups.

Another study evaluated metabolic parameters in 4657 adults from the American NHANES (National Health and Nutrition Examination Survey), 579 of whom were current marijuana users. They found that current users had a 16% lower fasting insulin level, and had less insulin resistance as well  (17% lower HOMA-IR, for the scientists in the audience), suggesting a lower risk of developing type 2 diabetes. Use of marijuana in this study was associated with smaller waist (a crude way to measure abdominal visceral fat - which contrasts with the findings in the first study above).

Other than these studies, there is very little data on marijuana and its effect on diabetes risk.

At this point, the available data does not suggest that marijuana carries the increased risk of developing diabetes that cigarette smoking does, with one study suggesting that it may even be protective of developing diabetes. However, the data is extremely limited, and further study of the effects of marijuana is much needed.

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Mediterranean Diet May Slow Brain 'Shrinkage' With Age

The Mediterranean style of eating seems to be rising above most other dietary plans for its health benefits.  Studies have shown that the Mediterranean diet may reduce the risk of cardiovascular events, and may also decrease the risk of breast cancer. A new study shows that the Med diet may also slow age related brain atrophy (natural 'shrinkage' of the brain with aging).

(Pictured above is the brain of a person in their 20s, compared to a person in their 80s, showing the natural atrophy that happens in the brain over time.)

The study, published in the journal Neurology, examined brain volumes and brain cortical thickness in Scottish people age 73, and followed them for three years until age 76.  They assessed eating patterns using questionnaires at age 70 (three years before the start of the study).   They found that people who reported less adherence to a Mediterranean style of eating had a greater reduction in total brain volume from age 73 to age 76, than those who reported eating in the Mediterranean style.

While this study is of lower quality than the randomized controlled clinical trial showing the cardiovascular and breast cancer benefit, it is another arrow pointing towards the benefits of the Mediterranean style of eating.   While no diet has been shown to be superior to another for weight loss, the health benefits of the Mediterranean diet continue to impress.

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