It’s near impossible to escape the news headlines concerning the rise in obesity, but despite this it’s hard to ignore all that delicious sugary and full-fat goodness lining the supermarket shelves. Obesity is known to increase the risk of developing health complications such as type-II diabetes and cardiovascular disease. On other end of the nutritional spectrum, undernutrition and deficiencies in various vitamins and minerals (e.g. vitamin D, calcium, iron) can also be detrimental to an individual’s wellbeing. However, how your body develops and functions is not necessarily all about your lifestyle and what food you put in your own body. There is increasing evidence that the mother’s diet before and during pregnancy can also affect the child’s health in later life.
Developmental Origins of Health and Disease
The Developmental Origins of Health and Disease (DOHaD) hypothesis suggests that the environment a baby is exposed to during pregnancy affects the long-term health of the offspring via physiological adaptations during pregnancy, which carry on into adult life. Interesting right?! So this hypothesis arose from numerous epidemiological studies in human populations worldwide, which found that a low birth weight was a risk factor for developing various diseases in adult life. Results from the Hertfordshire Cohort Study found that a low birth weight was linked to an increased risk of high systolic blood pressure , coronary heart disease , type-II diabetes  and osteoporosis .
Skeletal muscle is key
Skeletal muscle is one of the main sites for glucose handling. Having good skeletal muscle health is important for whole body metabolic function, strength and also mobility/stability. What a mother ate whilst she was pregnant may impact on her baby’s muscle function in adulthood, and so my PhD is exploring how various diets during pregnancy can affect skeletal muscle development and function in the offspring.
Maternal diet and the life trajectory of skeletal muscle
The intrauterine environment is believed to be important for the development and growth of skeletal muscle, which consequently determines peak muscle mass and strength in adult life, and as a result impacts on its decline with ageing – see the figure below!
Studies have found a link between birth size and adult muscle mass and strength. Low birth weight (an indicator of poor maternal conditions during pregnancy) and a reduction in muscle strength was found in a study of 717 elderly men and women born in Hertfordshire between 1920 and 1930 . This same relationship has also been observed in other studies of varying age groups, and all of these findings suggest that a suboptimal maternal environment during pregnancy may increase the risk of muscle wasting and impaired skeletal muscle function in later life.
Studies investigating the effect of maternal overnutrition or undernutrition have observed differences in the offspring muscle. A research group based at The Royal Veterinary College in London found that feeding female rats a high-fat/high-sugar diet during pregnancy impaired offspring muscle development. In 21-day old pups they found a decreased number and size of muscle fibres, and an increase in the amount of fat deposited within the muscle . Another group based at King’s College London found that feeding an obesogenic diet in pregnancy caused reduced activity levels and decreased muscle mass in young mouse offspring . On the other end of the scale, researchers from my lab group at The University of Southampton found that nutrient restriction in the mother before implantation or in the later phase of pregnancy also coincided with a reduction in the triceps brachii muscle fibre density in the fetal sheep .
But what nutritional drivers might alter this trajectory?
To explore this whole concept further my PhD is mainly focusing on how vitamin D deficiency in the pregnant mother affects offspring muscle. Vitamin D deficiency is highly prevalent in pregnant women, as well as the rest of the population. It is known to be important for various physiological processes such as calcium handling and bone formation, but research suggests that this vitamin is also important for skeletal muscle. Interestingly, vitamin D deficiency is associated with obesity as the increased fat tissue is thought to sequester vitamin D so it can’t be used by the body. So, to make it a little more complex (because PhDs are never straight forward!) I’m also looking at a high-fat pregnancy model to explore the relationship between obesity, vitamin D and muscle.
Well there you have it, the overall concept of my PhD! In future posts I’ll be divulging into the more specifics of the experimental models I’ve been using and revealing some of my findings so far, so watch this space!
Take home message: you might not be the only one who’s affected by what you eat and the lifestyle you choose!