Are you a fake skinny? Appearances are deceiving, biomarkers are not.

Besides COVID-19, there is another silent pandemic plaguing society: obesity. Globally, 39% of adults are estimated to be overweight or obese. This diagnosis is based on body mass index (BMI), calculated using a formula that includes body weight and height. However, is this parameter representative of metabolic health? Or is this rather the tip of the iceberg?

BMI vs visceral fat (0-1)

While BMI is a useful measurement as a first approximation, scientific evidence shows that it is not enough and there are examples available to everyone. Based on BMI, a short bodybuilder who weighs more muscle than fat can be classified as overweight, even in good health. On the contrary, a tall and thin person, but with a “beer belly”, can be attributed to normal weight, even if his metabolism is changed.

This last group is commonly referred to as “false thin” (LF) and is defined as follows: individuals with a BMI indicating normal weight, but with a high percentage of body fat, mainly at the visceral level (associated with the abdominal organs).

Currently, FDs are an exception to the most important BMI classification: they are estimated to represent up to 22% of the world’s population.

Consequences of (fake) thinness

The presence of an excessive amount of fat in the body disrupts the regulation of the entire metabolism in the body. Let’s start with the fact that in false skinny generalized inflammation, changes in blood lipids, arterial hypertension, and insulin resistance are more common. etc.

These deregulations lead to a dramatic increase in the risk of developing chronic pathologies such as diabetes or cardiovascular disease in FD. In fact, at least in women with FD, the mortality rate doubles. Therefore, it is a major public health issue that needs to be studied for prevention and treatment.

But how is this state achieved? In the Nutrigenomics, Biomarkers and Risk Assessment (NuBE) group of UIB, we have been studying this phenomenon in rodents for many years and we know perfectly well what conditions must be met in order for them to develop the FD condition. Mostly unbalanced diet (for example, high in fat), but without a calorie surplus. That is, eat badly, but in moderation. There is even evidence that maternal malnutrition during lactation may also contribute to the onset of FD in offspring.

The same thing happens with people. Each of us has a typical friend who abuses fast food and does not get fat. Although it is not visible to the naked eye, it is possible that you are storing fat at the visceral level. If we add to this unbalanced diet (rich in sugars and fats) the current sedentary lifestyle, lack of exercise, stress and unfavorable genetics, we have the perfect recipe for creating a population of falsely skinny people.

Top tips for your metabolic health

Once the reasons are clear, it is equally important to try to avoid it. It would probably be useful to be able to give advance warning of the risk of developing a FD condition. To this end, in the NuBE group, we are researching predictive biomarkers. That is, parameters that can be objectively measured when a person is healthy, indicating early problems that are otherwise unnoticeable. For example, elevated blood glucose levels can be a biomarker for diabetes.

Theoretically, the ideal biomarker should be inexpensive, minimally invasive, and fast. And what biological samples match these characteristics? Those that can be obtained with simple procedures: urine, saliva or blood.

The latter are widely studied, since capturing cells are found in the blood: peripheral blood mononuclear cells (PBMCs, Mononuclear cells in peripheral blood). They are in constant circulation, interact with all our tissues and can reflect what is happening in other parts of our body. That is, if a gene is overexpressed in the brain, that gene can also be overexpressed in PBMCs.

How do they work? It will be like a game of “broken phone”: something happens to your friend Alba, she tells Pedro, and he tells you. Surely the version that Pedro will tell you will be very similar to what is actually happening with Alba, although with some variations. Alba will be the liver, the tissue that goes through a lot of changes in BF, and Pedro will be the RVMS who will tell you his version of what happens to the liver.

Thus, by analyzing the expression of PBMC genes, one can find out what is happening in other internal organs. For all these reasons, PBMCs are increasingly being used in the scientific community to identify biomarkers not only in nutrigenomics and obesity research, but also in other fields such as neuroscience.

Without a healthy body, there is no healthy mind.

We are an extremely complex organism with all its interconnected systems. In fact, both obesity and FD are associated with neurodegeneration. The most common dementia is Alzheimer’s disease, and there is no cure for it. It is predicted that more than 115 million people will suffer from it by 2050.

Here again, the RVMS play a leading role. The NuBE group showed that these cells are capable of early reflection of cognitive impairment in FD rats. And this was confirmed by a clinical trial involving 360 people over 60 years old, conducted by Shishuang Zhang and his collaborators at Tianjin Medical University. Therefore, the detection of these biomarkers will avoid invasive procedures such as biopsy. And, being early, it can be vital in preventing chronic disease.

Better to prevent than to cure

Once these biomarkers are improved, we will be able to determine in advance whether a person is more prone to false thinness and the associated risks. What then? Well, for these people, preventive action would be a higher priority.

The necessary measures are the same as for other non-communicable diseases: lead a healthy lifestyle. That is, observe a balanced diet, exercise, rest and, of course, good mental health.

And the fact is that, while appearance is still relevant, health is marked – or biomarked – primarily by what happens inside of us.

This paper was the winner of the 3rd University of the Balearic Islands Scientific Dissemination Competition..

Carmen Garcia Ruano, FPU Fellow. Nutrigenomics, Biomarkers and Risk Assessment (NuBE) group. UIB, Siberobn, IdISBa, University of the Balearic Islands; Juana Sanchez Roig, professor of biochemistry and molecular biology. UIB, Siberobn, IdISBa; Paula Oliver Vara, professor of biochemistry and molecular biology. Nutrigenomics, Biomarkers and Risk Assessment (NuBE) group. UIB, Siberobn, IdISBa, University of the Balearic Islands and Pere Bibiloni Call, FPU Fellow. Nutrigenomics, Biomarkers and Risk Assessment (NuBE) group. UIB, Siberobn, IdISBa,, University of the Balearic Islands

This article was originally published on The Conversation. Read the original.