There are many different types of fats, some of which are simply used for energy, while others have a powerful effect on health.
Conjugated linoleic acid (hereafter all referred to as cla) is a fatty acid found in meat and dairy products and is thought to have a variety of health benefits. It is also a popular weight loss supplement.
This time we will discuss the effects of cla on fat loss and overall health.
What is cla?
Linoleic acid is the most common omega -6 fatty acid and is found in large amounts in vegetable oils and in small amounts in a variety of other foods.
"Conjugation" Relates to the arrangement of the double bonds in the fatty acid molecule.
There are 28 different forms of cla.
They differ in the way their double bonds are arranged. It is important to remember that something as small as this can have a huge impact on our cells.
Cla is essentially a polyunsaturated omega-6 fatty acid. In other words, it is technically a trans fat, but it is a natural trans fat that is found in many healthy foods.
Industrial production of trans fats, unlike natural trans fats like cla, artificially produced trans fats are harmful when consumed in large quantities.
Cla is a trans fat-6 fatty acid. However, it is very different from industrially produced trans fats which are hazardous to health.
Found in beef and dairy products, especially from herbivores
The main dietary sources of cla are the meat and milk of ruminants, such as cattle and sheep.
The total amount of conjugated linoleic acid in these foods varies considerably depending on the animal's diet.
For example, grass-fed cattle have 300-500% more cla in their beef and dairy products than grain-fed cattle.
Most people already consume some cla through their diet. The average daily intake for women in the us is about 151 mg and 212 mg for men.
Now, the conjugated linoleic acid you find in many nutritional products does not come from natural foods, but from a chemical change in linoleic acid found in vegetable oils.
As a result, many conjugated linoleic acid supplements do not provide the same health benefits as conjugated linoleic acid in food.
The main dietary sources of cla are dairy products and meat from cows, goats and sheep, while many cla supplements are made from chemically altered vegetable oils.
Can it help burn fat and lose weight?
The biological activity of conjugated linoleic acid was first discovered by researchers who noticed that conjugated linoleic acid could help fight cancer in rats.
Later, other researchers believed that it could also reduce body fat levels.
With the increase in obesity worldwide, cla is also being used as a potential weight loss method.
In fact, cla is probably one of the most well-researched all-purpose weight loss nutrients in the world.
Cla has been shown through animal studies to reduce body fat in a variety of ways.
In mouse studies, it has been found to reduce food intake, increase fat burning, stimulate lipolysis and inhibit lipogenesis.
Cla has also been extensively studied in randomised controlled trials, the gold standard for scientific trials in humans, although results have been mixed.
Some studies have shown that conjugated linoleic acid can lead to substantial fat loss in humans. It can also improve body composition by reducing body fat and increasing muscle mass.
However, there are also many studies that show no effect at all.
In a controlled trial of 18 studies, cla was found to reduce fat moderately.
This effect is most pronounced in the first six months after weight loss, after which the effect plateaus over the next two years.
Overall, cla was found to be more effective than other similar supplements for weight loss.
Although natural conjugated linoleic acid supplements are associated with fat loss, their effects are small, uncertain (controversial) and unlikely to have an impact on daily life.
Potential health benefits
In nature, cla is found mainly in fatty meat and dairy products from ruminants.
Many long-term observational studies have assessed the risk of disease in populations consuming high levels of cla.
Notably, people who get high amounts of cla from their food have a lower risk of various diseases, including type 2 diabetes and cancer.
In addition, studies conducted in countries where cows eat mainly grass rather than grains have shown that people with the highest levels of cla in their bodies have a lower risk of heart disease. However, this low risk may also be caused by other protective components in the products of grass-fed animals, such as vitamin k2.
Of course, there are various other reasons for the health of grass-fed beef and dairy products.
Many studies have shown that people who eat the most cla are metabolically healthier and have a lower risk of many diseases.
High doses can cause serious side effects
There is evidence that getting small amounts of natural cla from food can be beneficial.
However, many of the clas found in supplements are made by chemically altering linoleic acid in vegetable oils. They are usually in a form different from the cla naturally present in food.
Supplement doses are also much higher than the doses people consume from dairy products or meat.
Often, some molecules and nutrients are beneficial in the natural content of foods, but can be harmful if consumed in large amounts. Studies have shown that this is also the case with cla supplements.
High doses of conjugated linoleic acid can lead to liver fat accumulation, a stepping stone to metabolic syndrome and diabetes. Numerous studies in animals and humans have shown that cla can cause inflammation, cause insulin resistance and lower "Good" Hdl cholesterol.
Keep in mind that many of the relevant animal studies used doses much higher than those obtained from supplements in humans.
However, some human studies using reasonable doses have shown that cla supplementation may cause some mild or moderate side effects, including diarrhoea, insulin resistance and oxidative stress.
The conjugated linoleic acid found in most supplements is not the same as that found naturally in food.
Dosage and safety
Most cla studies have used doses of 3.2-6.4 g per day.
One review concluded that at least 3 grams per day is necessary for weight loss.
Doses of up to 6 grams per day are considered safe and no serious adverse side effects have been reported in people.
However, it is important to remember that the risk of side effects increases with increasing dose.
Studies have shown that conjugated linoleic acid has a limited effect on weight loss.
Although doses of up to 6 grams per day do not cause any serious side effects, there are concerns about the long-term health effects of supplemental doses.
We therefore recommend that if not specifically required, it is better to consume as much as possible from natural foods.