Obesity: can it “run in the family”?

We have often seen that obese parents will have children who are also obese. Is this just due to lifestyle or is there something else going on?

A recent study published in the journal Cell Reports investigated the effect a mother’s metabolic syndrome had on her offspring. The investigators conducted the study using mice so obviously caution should be used when extrapolating the results to humans, however, apart from the obvious advantage of being able to study several generations in a short period of time, it does show some interesting insights into what could be going on in the human population.

A quick recap, metabolic syndrome is a term given to a group of conditions that are all risk factors for cardiovascular disease and tend to cluster together. They are

• ·         Insulin resistance
• ·         Abdominal obesity
• ·         Glucose intolerance (fasting plasma glucose ≥ 6.0 mmoll/L)
• ·         Hypertension
• ·         Dyslipidaemia

A patient is considered to have metabolic syndrome if they are insulin resistant and have at least two of the other following conditions¹. Obese individuals tend to develop the other conditions over time and although currently there seems to be a group who define themselves as “obese but metabolically healthy”, recent evidence appears to show that they are simply at the start of the path towards metabolic syndrome (see our post on health at any size).   

Back to the study². The authors wanted to investigate whether the offspring of an obese mother with metabolic syndrome inherited a predisposition for the syndrome and obesity.

The mothers were fed a diet of high fat and high sugar from birth and all developed obesity and metabolic syndrome. The children (not sure if that’s the right word), grandchildren and great-grandchildren were all fed a standard rodent diet after weaning. The standard diet was high in protein and low in sugar and fat.

The authors found that the female offspring of the obese mothers had “impaired peripheral insulin signalling” associated with “mitochondrial dysfunction” and that this could pre-programme the offspring to develop insulin resistance and of course start on the metabolic syndrome journey. What was surprising and also alarming was that the mitochondrial dysfunction was passed through the female bloodline to the grandchildren and great-grandchildren despite them eating a healthy diet!

The authors concluded that despite following a normal diet, early exposure to metabolic syndrome (through mother) caused an inheritance of a pre-programmed risk of developing insulin resistance in female offspring that was passed through 3 generations. They also concluded that as human offspring tend to eat the same as the rest of the family, if this pre-programming occurs within humans coupled with the continued exposure to a high fat high sugar diet would lead a high risk of those children developing metabolic syndrome in adult life.

An interesting study that offers another layer to the complex issue of obesity. We know that babies born to obese mothers tend to be large for gestational age and have an increased risk of developing obesity. What is worrying is that if the same mitochondrial dysfunction occurs in humans, that mother’s grandchild and even great grandchild will be born with an increased risk of developing insulin resistance regardless of their diet. 

With around 60% of childbearing age mothers in the USA being obese and us Europeans catching them up, this could lead to the “epidemic” of obesity not only growing but also being endless!!!

For more info on our healthy eating programmes please contact info@gabinetederueda.es

References

1.          C Geissler & H Powers 2005,Human nutrition 11^th Edition. Elsevir
2.           Jessica L. Saben, Anna L. Boudoures, Zeenat Asghar, ..., Andrew Cusumano, Suzanne Scheaffer, Kelle H. Moley. 2016 Maternal Metabolic Syndrome Programs Mitochondrial Dysfunction via Germline Changes across Three Generations Cell Reports 16, 1–8