As the first independent scientific session of the American Society for Nutrition, Nutrition 2018 rewarded attendees with mind blowing research findings from all over the world and offered a dynamic platform for researchers to communicate and network. Research on nutrition science has evolved to a stage where not only what people eat is of interest, but the accessibility of food, as well as the impact of eating behaviors, gut microbiota and physical activity are all integral to addressing key issues such as obesity and delivering healthy lifestyles.
Vegetarian diet has a variety of health benefits
According to a 13 year Netherlands-based study, including almost 6,000 subjects, people who consumed more plant protein than animal protein had a lower risk of developing coronary heart disease. Another study from Brazil concluded that, of the 4,500 participants, those who consumed more plant protein than animal protein were 60% less likely to have plaques inside their arteries, an independent risk factor of atherosclerosis.
The quality of plant-based diets is also important. An analysis of over 125,000 adults found that body weight changes over a 4-year-period were associated with the quality of plant-based diets. Diets rich in high quality plant foods including whole grains, fresh fruit, vegetables and nuts, were associated with significantly lower weight gains compared to diets rich in refined carbohydrates and fried food.
Another study on almost 30,000 US adults confirmed that consumption of high quality plant-based foods are associated with a 30% reduction in mortality rate compared to those not consuming such food, and the benefit is especially profound among people who had pre-existing chronic conditions.
In an oral presentation Professor Frank Hu from Harvard University also discussed the benefits a plant-based diet compared to diets containing meat. He described how plant-based diets are associated with higher diet quality, lower risk of type 2 diabetes and coronary heart diseases, and lower long-term weight gain.
“Prof Hu emphasized the need to look at more than just calories and that to move forward in addressing the key issues in nutrition we need to assess dietary quality”
Prof Hu emphasized the need to look at more than just calories and that to move forward in addressing the key issues in nutrition, we need to assess dietary quality, taking into consideration how the food is prepared and what ingredients are added on top of macronutrients.
Food in the workplace contributes to obesity
A large scale study presented by Dr Stephen Onufrak at the Centers for Disease Control and Prevention (CDC) discovered that the food people consume in their places of work, whether it was purchased from vending machines or free food provided by the company , were usually high in salt, added sugars or solid fats. These unhealthy foods that people had easy or free access to at work, could result in an extra intake of up to 1,300 calories per week, according to the survey of 5,222 employees in US.
The study found that one-quarter of participants obtained food from work at least once a week. These 1,300 additional calories would require at least two hours of aerobic exercise, such as jogging or swimming to burn off. But this also means that employers can do something to improve the food environment for their employees, by providing easy access to healthy food options at work.
Make your metabolism flexible
Metabolic flexibility refers to our body’s ability to shift between different sources of energy, particularly between burning fat and using glucose. In healthy subjects the metabolism is supposed to be flexible, so the body will use fatty acids (from the intake of fat) as its main energy source when maintaining a low-to-medium level of physical activity and switch to carbohydrates as the preferred energy source when the intensity of physical activity increases.
Dr Eric Ravussin shared with us that, metabolic flexibility is affected by diet, sedentary behaviors and physical activity. Unhealthy diets and lifestyles including lots of refined carbohydrate, added sugar and sedentary behaviors are associated with metabolic inflexibility, meaning the body has difficulty in switching to using fat as an energy source. In the long term this can lead to a lot of serious health issues, as it means the body is constantly in need of carbohydrate, as it cannot use stored fat as an energy source.
Frequent consumption of carbohydrates leads to spikes in insulin levels, which over time makes the body insensitive to insulin and therefore less able to respond to this signal hormone which can eventually lead to type 2 diabetes. As such, metabolic flexibility is an important potential target for therapies aiming to improve people’s metabolic health.
Gut microbiota: an unsolved puzzle
Gut micriobiota have been identified as an essential factor regulating metabolism and have the potential to affect our health; this is especially the case for the microbiome inside the bowel.
According to the presentation by Dr Daniel McDonald, on behalf of the American Gut Project, diet can significantly affect the chemistry inside the gut. Researchers have been using a crowdsourcing approach to collect samples in a large scale study. They compared human gut microbiome samples from different countries and to environmental samples such as water or food.
To date they have found that the diversity of plants in the diet is heavily associated with molecular features of the microbes inside the gut, and that stress (like surgery) can have significant impact on human gut microbiota. With their ongoing research, they are hoping to unveil more details about the gut environment and what the microbes within it produce, and to answer questions relating to how the gut environment interacts with food intake and stress.