Mediterranean Diet With Olive Oil Prevents Breast Cancer

It's tough to navigate all of the health claims of various food products out there.  Many claims are unsubstantiated, and those that have evidence behind them are often not derived from high quality data.  In that context, I was impressed to see a recent randomized controlled clinical trial, suggesting that a Mediterranean diet supplemented with extra virgin olive oil reduces the risk of breast cancer in postmenopausal women.

The PREDIMED trial randomized 4,282 women to receive either a Mediterranean diet supplemented with extra virgin olive oil; a Mediterranean diet supplemented with nuts; or a control diet with advice to reduce dietary fat.

After 4.8 years, they found that the olive oil supplemented diet reduced the risk of breast cancer by 62%, and the nut supplemented diet reduced the risk by 41%, compared to the control diet.

While these numbers look super impressive, the absolute numbers are actually fairly small: rates of breast cancer per 1000 person years were:

• 1.1 for the extra virgin olive oil group
• 1.8 for the nuts group
• 2.9 for the control group

Still: what this means is that if 1000 women eat following the Mediterranean + oil diet, roughly 2 cases of breast cancer would be prevented.

While the total number of breast cancer cases in the entire study was small (35 total), and only included postmenopausal caucasian women at high risk of vascular disease, the results are certainly interesting and worthy of further research in broader and larger populations.  One must also be careful not to eat too many calories in oil or nuts - these are highly calorie dense foods which can quickly add up and contribute to weight struggles if eaten to excess, and obesity is a known risk factor for breast cancer.

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Diabetes Medication Empagliflozin Saves Lives

In follow up to the press release I blogged about last month, we now have the data which has rocked the foundation of the diabetes world:  the diabetes medication empagliflozin has been found to reduce the risk of cardiovascular deaths and all cause mortality in patients with type 2 diabetes and cardiovascular disease.

The EMPA-REG study, published by Canadian Dr Bernie Zinman and colleagues in the New England Journal of Medicine, randomized 7020 people with type 2 diabetes and established cardiovascular disease to receive either empagliflozin 10mg, empagliflozin 25mg, or placebo, in addition to their usual care.

After a median of 3.1 years, they found that there was a significantly lower risk of death from cardiovascular causes (3.7% on empagliflozin vs 5.9% in the placebo group), a reduced risk of death from any cause (5.7% on empagliflozin vs 8.3% on placebo), and a reduction in hospitalization for heart failure (2.7% on empagliflozin vs 4.1% on placebo).

Put another way: empagliflozin decreased the risk of hospitalization for heart failure by 35%, reduces the risk of death from cardiovascular causes by 38%, and reduced the risk of death from any cause by 32%.

Put yet another way:  if 39 people were treated with empagliflozin for 3 years, one death was prevented.  This number is very comparable to the power of other medications that we use to prevent cardiovascular disease and death in people who are at high risk:  for example,

• simvastatin (a cholesterol medication): treating 30 people for 5.4 years prevents one death
• ramipril (a blood pressure medication): treating 56 people for 5 years prevents one death

These results are truly landmark, in that we have never before definitively proven that any diabetes medication clearly reduces the risk of cardiovascular disease or death.  There are two other medications in this class of diabetes medications (called SGLT2 inhibitors) which are available in Canada (canagliflozin (Invokana) and dapagliflozin (Forxiga)).  These medications have similar studies underway, but results are still a couple of years away. 

The EMPA-REG results have caused diabetologists around the world to have to reconsider current practice guidelines for type 2 diabetes, and whether this class of medications should take priority in the selection of treatment for our patients.   While it is always of paramount importance to consider benefits and risks of any medication, this data certainly suggests that the SGLT2 inhibitors should be considered high on our list of choices for treatment of type 2 diabetes.

Disclaimer: I receive honoraria as a continuing medical education speaker and consultant from the makers of empagliflozin (Boehringer-Ingelheim and Eli Lilly), canagliflozin (Janssen), and dapagliflozin (Astra Zeneca).  I am involved in research of SGLT2 inhibitors as a treatment of diabetes.

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Does Gastric Bypass Surgery Increase Energy Burn?

We know that Roux-en-Y gastric bypass surgery is effective to induce weight loss, causing an average weight loss of about 40% of total body weight.  How this actually happens is still far from completely understood.   Many mechanisms are likely at play, but one of the most hotly debated is whether energy burn (called energy expenditure) goes up, down, or does not change after gastric bypass surgery.

We have recently published the results of our randomized, controlled clinical trial in gastric bypass patients, to add to our understanding of this complex area.

In this trial, conducted at the University of Copenhagen and published in the International Journal of Obesity, we enrolled 28 patients, and placed them on a low calorie diet (1000 kcal/day) in preparation for their gastric bypass surgery.  Patients were randomized to have surgery either 8 weeks or 12 weeks after the start of the low calorie diet, such that we could compare them just before the second group had surgery.  (This protocol enabled us to use a 'pair-fed' control model, as there have been criticisms of other studies comparing post surgical patients to control groups who are eating totally differently, not on a low calorie diet, and not on a negative weight trajectory.)  We then repeated testing on the entire group at 1.5 years post surgery.

We found that at 3 weeks postoperatively, patients had lower body composition-adjusted 24 hour and basal energy expenditure compared to those who had not yet had their surgery.  However, at the 1.5 year mark, patients' energy expenditure was not different compared to their own preoperative values.   We also found that surgery increased the postprandial response to many hormones, including GLP-1, PYY, bile acids, and FGF-19.  Decreases in appetite were particularly associated with increased GLP-1, increased PYY, and decreased ghrelin.

So, our study suggests that the decrease in weight seen after gastric bypass surgery is not caused by an increase in energy expenditure, but that weight loss is more likely to be mediated by hormonally-induced changes in appetite.

An enormous and heartfelt thank you to my ex-PhD student (now postdoc!) Dr Julie Berg Schmidt, and all of my dear colleagues at the University of Copenhagen, for years of fantastic collaboration to bring this study to fruition!  Stay tuned for many more publications stemming from this trial.

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Could Bariatric Surgery Cure My Diabetes?

Clinicians out there – have you ever been asked this question?

I get asked this question at least once a day.

There is an expanding body of data demonstrating the powerful ability of bariatric surgery to improve control of type 2 diabetes, and even put it into remission.  However, we are lacking in long term data on this important topic, with most higher quality data only being available to 2 years post surgery.  For the first time, we now have data from a randomized clinical trial to tell us a little more about what happens to patients with type 2 diabetes, 5 years after bariatric surgery. (Skip to 'So, my take on this?' below if you don't want the study details)

The study, published this week in The Lancet by Mingrone and colleagues, randomized 60 patients to receive either gastric bypass surgery (n=20), biliopancreatic diversion (BPD, n=20), or medical treatment (n=20) for their type 2 diabetes.  Participants were age 30-60, and had to have type 2 diabetes for at least 5 years.  Almost half of the patients in the study were using insulin as part of their diabetes treatment.  

The key findings of the study were:

• ·             At 5 years after surgery, 37% of patients who had gastric bypass, 73% of patients who had BPD, and none of the patients in the medical treatment group, were in remission from their diabetes.
• ·             About half of patients who achieved diabetes remission at 2 years, had relapsed by 5 years (in other words, their diabetes came back). However, when their diabetes came back, it required less medication and was under better control than before the surgery.
• ·             Amount of weight lost did not predict who would go into diabetes remission (or who would relapse).
• ·             Cardiovascular risk (defined as a composite endpoint of at least 2 parameters including reduction in heart/diabetes drugs and improvement in diabetes, cholesterol, or blood pressure control) decreased more in surgically treated groups.
• ·             Five major diabetes complications were seen in patients in the medical group, vs one in the gastric bypass group and none in the BPD group.

So, my take on this? These findings support what we have seen in previous nonrandomized 5 year data: bariatric surgery can be quite powerful to put diabetes into remission (with variable effect depending on the type of surgery), but by 5 years, about half of the diabetes cases come back.  This is a small study, but kudos to the study authors, as I know from my own experiences that it is very difficult to conduct randomized controlled clinical trials in this area.  That the amount of weight loss did not predict the effect of the surgery on diabetes reminds us of the powerful impact of other mechanisms of these surgeries on blood glucose control (for example, changes in gut hormone production).

It’s important to note that while diabetes complications were lower in the surgery group, the surgical and surgically related metabolic complications were (of course) higher in the surgical groups.  These risks were highest in the BPD group, which is a rather dramatic and extensive intestinal bypass procedure.  BPD is not accepted as a standard surgery due to the risk of complications, and in most places BPD is only available in a research setting.

Bariatric surgery can be a powerful and effective treatment for type 2 diabetes for the right individual, who is comfortable with the risk vs benefit profile of surgery, and for whom the benefits clearly exceed the risks.  Patients who experience remission of their diabetes after surgery need to be followed lifelong, as the diabetes can certainly come back.

Follow me on twitter! @drsuepedersen

www.drsue.ca © 2015

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