Thermogenics: possible contraindications and side effects.
3 min
Did you know?
More and more often we see products called "thermogenics" whose purpose is to reduce body weight and excess fat. Today we want to examine whether these thermogenic supplements have contraindications or side effects and, if so, of what kind.
First of all it is important to remember how energy expenditure works: it comprises basal metabolism, physical activity and thermogenesis. This will help us understand why these products appeared on the supplement market.
We have already talked about basal metabolism : in a nutshell, it is the energy we use at rest. Basal metabolism depends on genetic, nutritional and metabolic factors, and varies according to a person's sex, age, height and weight.
Physical activity is another factor that causes energy to be "used up"; it varies according to the intensity and duration of the exercise or work we do, as well as its frequency.
Thermogenesis, on the other hand, is determined by the thermic effect of food and accounts for about 15% of energy expenditure. Eating food produces 'heat' over and above basal metabolism. It is influenced by food intake, exposure to cold, stress, and thermogenic substances and hormones.
A mixed diet can increase the calories spent on heat production by 6-10% above the baseline value (Rosenberg, 1994).
It has been found that some foods can cause greater thermogenesis than others: the greatest stimulus comes from proteins and amino acids (10-35% of the energy ingested), while lower values are attributed to carbohydrates and lipids. This explains why so many protein-based diets are so popular, and they are not only useful for building lean mass (muscle), as is often believed.
The so-called thermogenics on the market include several categories of products: they are based on stimulant substances that can boost metabolism (caffeine, ginseng, synephrine, guarana, iodine etc.), proteins, laxatives and dietary fibres, which reduce the absorption of nutrients, increase intestinal motility and stool production and create a feeling of fullness that influences the amount of food we eat during the day.
Just recently the European Community authorised some 'claims' on certain fibres, after examining several related scientific studies that demonstrated their effectiveness. The same cannot yet be said for other substances.
Thermogenic supplements come as pills, capsules, tablets and powders.
They are generally well tolerated at the recommended doses; however, it is important to bear in mind some possible contraindications or side effects at higher doses:
- Iodine is not suitable for people with hyperthyroidism, as it can worsen a state of thyrotoxicosis, with symptoms such as tremors, tachycardia and insomnia.
- caffeine and the extracts that contain it, such as guarana and cola, increase heart rate; synephrine and ginseng also raise blood pressure. These substances should therefore be taken at the indicated doses without exceeding them, consulting your doctor first if you have any medical conditions, especially in the case of older people or people with heart disease.
- The proteins place a greater workload on the liver and kidneys in proportion to the amount taken, with a significant increase in nitrogenous catabolites. People with liver disease or kidney failure must therefore reduce the amount, in any case seeking their doctor's advice.
- The fibres increase the workload of the intestine (peristalsis) and must therefore be taken with caution in the presence of inflammatory processes such as colitis and Crohn's disease. They should also be taken with plenty of water to avoid swallowing difficulties, particularly in people with dysphagia.
- Herbal teas based on plant extracts such as senna, rhubarb, alder buckthorn, cassia and others have a genuine laxative and potentially dehydrating action. Moreover, if used frequently they can lead to dependence, with resulting constipation as soon as you stop taking them. Finally, they are clearly contraindicated for anyone who does intense physical activity.
A separate note is deserved by ephedrine or Ma Huang, a thermogenic substance that is currently banned and classed as doping, found until a few years ago mainly in American products and linked to cases of stroke and cardiac arrhythmias, some of them fatal.
In conclusion, which thermogenic should you choose?
Discover the most suitable products in the dedicated section.
More and more often we see products called "thermogenics" whose purpose is to reduce body weight and excess fat. Today we want to examine whether these thermogenic supplements have contraindications or side effects and, if so, of what kind.
First of all it is important to remember how energy expenditure works: it comprises basal metabolism, physical activity and thermogenesis. This will help us understand why these products appeared on the supplement market.
We have already talked about basal metabolism : in a nutshell, it is the energy we use at rest. Basal metabolism depends on genetic, nutritional and metabolic factors, and varies according to a person's sex, age, height and weight.
Physical activity is another factor that causes energy to be "used up"; it varies according to the intensity and duration of the exercise or work we do, as well as its frequency.
Thermogenesis, on the other hand, is determined by the thermic effect of food and accounts for about 15% of energy expenditure. Eating food produces 'heat' over and above basal metabolism. It is influenced by food intake, exposure to cold, stress, and thermogenic substances and hormones.
A mixed diet can increase the calories spent on heat production by 6-10% above the baseline value (Rosenberg, 1994).
It has been found that some foods can cause greater thermogenesis than others: the greatest stimulus comes from proteins and amino acids (10-35% of the energy ingested), while lower values are attributed to carbohydrates and lipids. This explains why so many protein-based diets are so popular, and they are not only useful for building lean mass (muscle), as is often believed.
The so-called thermogenics on the market include several categories of products: they are based on stimulant substances that can boost metabolism (caffeine, ginseng, synephrine, guarana, iodine etc.), proteins, laxatives and dietary fibres, which reduce the absorption of nutrients, increase intestinal motility and stool production and create a feeling of fullness that influences the amount of food we eat during the day.
Just recently the European Community authorised some 'claims' on certain fibres, after examining several related scientific studies that demonstrated their effectiveness. The same cannot yet be said for other substances.
Thermogenic supplements come as pills, capsules, tablets and powders.
They are generally well tolerated at the recommended doses; however, it is important to bear in mind some possible contraindications or side effects at higher doses:
- Iodine is not suitable for people with hyperthyroidism, as it can worsen a state of thyrotoxicosis, with symptoms such as tremors, tachycardia and insomnia.
- caffeine and the extracts that contain it, such as guarana and cola, increase heart rate; synephrine and ginseng also raise blood pressure. These substances should therefore be taken at the indicated doses without exceeding them, consulting your doctor first if you have any medical conditions, especially in the case of older people or people with heart disease.
- The proteins place a greater workload on the liver and kidneys in proportion to the amount taken, with a significant increase in nitrogenous catabolites. People with liver disease or kidney failure must therefore reduce the amount, in any case seeking their doctor's advice.
- The fibres increase the workload of the intestine (peristalsis) and must therefore be taken with caution in the presence of inflammatory processes such as colitis and Crohn's disease. They should also be taken with plenty of water to avoid swallowing difficulties, particularly in people with dysphagia.
- Herbal teas based on plant extracts such as senna, rhubarb, alder buckthorn, cassia and others have a genuine laxative and potentially dehydrating action. Moreover, if used frequently they can lead to dependence, with resulting constipation as soon as you stop taking them. Finally, they are clearly contraindicated for anyone who does intense physical activity.
A separate note is deserved by ephedrine or Ma Huang, a thermogenic substance that is currently banned and classed as doping, found until a few years ago mainly in American products and linked to cases of stroke and cardiac arrhythmias, some of them fatal.
In conclusion, which thermogenic should you choose?
Discover the most suitable products in the dedicated section.
