In recent decades, alarming epidemiological figures have emerged that point to an obesity epidemic. As it indicated by the World Health Organization (WHO), the obesity and overweight are defined as abnormal or excessive fat accumulation that can be harmful to health . Currently the form used to measure obesity is the body mass index (BMI), this is the weight of a person in kilograms divided by the square of the height in meters. A person with a BMI equal to or greater than 30 is considered obese and with a BMI equal to or greater than 25 is considered overweight (1).
Worldwide according to WHO, in 2014, 39% of adults, over 18 years of age were overweight, and 13% were obese (2). While in Argentina, according to the latest National Survey of Risk Factors (ENFR, 2013), the prevalence of overweight was 37.1%, a value that remained constant with respect to the 2nd ENFR carried out in 2009, although it grew with respect to the evidenced in the 1st ENFR 2005 (34.4%). On the other hand, the prevalence of obesity was 20.8%, resulting in 15.6% higher than in 2009 (18%) and 42.5% higher than in 2005 (14.6%) (3).
For some years, overweight and obesity used to be considered a problem typical of high-income countries, but for some years this phenomenon is increasing significantly in low and middle-income countries , particularly in urban regions. The root cause of excess weight is an energy imbalance between calories consumed and spent
As evidenced by the increase in the numbers of people who are overweight and obese, it can be observed concomitantly how the pattern of food intake has changed. In recent years the supply of food products rich in calories has increased, with significant amounts of fats, salt and sugars but poor in vitamins, minerals and other micronutrients (4).
Immersed in this obesogenic environment, it is beginning to show that obesity is a public health problem that goes beyond mere energy balance , which also includes genetic, neuronal and endocrine factors (4) (5).
Relationship between obesity and neuronal deterioration
Regarding neuronal factors, recent studies show that certain specific foods, rich in saturated fats and / or simple sugars, very characteristic of a Western diet, can cause cognitive impairment. In some cases this deterioration is independent of the effects on body weight gain and obesity (5).
The mechanisms by which neuronal deterioration occurs are not fully described; In the latest reviews, it is considered that the inflammation of the neuroglia would be the trigger that triggers the damage, adding the oxidative stress produced by pro-inflammatory substances (6).
In this sense, the hippocampus is recognized as the region of the brain that modulates the signals related to the acquisition and consumption of food, through the detection and use of neurohormonal signals important for energy balance. Since its normal functioning is interrupted, it is difficult to moderate consumption and this further exacerbates the vicious circle that occurs in overweight and obesity (6).
How to prevent neuronal deterioration
To cope with oxidative stress, evidence indicates that eating foods with natural antioxidants (such as vitamin E and C, carotenoids, flavonoids) can prevent and even partially reverse the damage . Omega 3 polyunsaturated fatty acids have also been proposed to play a role in modulating the risk of cognitive impairment (6) (7).
In conclusion, it is evident that overeating saturated fats and / or simple sugars can impair cognitive functions. Considering the hippocampus as responsible for a series of functions, including episodic memory (that is, remembering what we have eaten), as well as our ability to respond to signs of hunger and internal satisfaction, special attention should be given to the quantity but also to the quality of the diet. Keep in mind that the oxidative stress that damages the hippocampus microglia can create a vicious cycle in which it is both the cause and consequence of overfeeding and obesity. Prevention is possible and is the point where action should be taken, promoting the consumption of antioxidant-rich foods and the development of activities that stimulate and exercise normal neuronal functioning.