The increasing prevalence of metabolic syndrome in recent years has aroused interest in exploring new dietary interventions capable of mitigating the pathologies associated with this condition. In this context, dietary fiber has proven to play an important role in the prevention and protection of these type of diseases. Consequently, it is increasingly necessary to identify new sources of fiber, and in that sense, seeds such as chia are profiled as an attractive and promising alternative.
A recent study1 led by Dr. Loreto Muñoz of the Central University of Chile, with the collaboration of Dr. Rodrigo Valenzuela and student Camila Cisternas of the University of Chile, investigated the effects of the fiber-rich fraction derived from partially defatted chia seeds (chia flour) in subjects with insulin resistance and hepatic steatosis induced by a high-fat diet. The study also examined their contribution to n-3 polyunsaturated fatty acids (PFAs) and short-chain fatty acids (CFAs).
Let’s talk to Dr. Muñoz to explain the extent of the results of her research.
Loreto Muñoz: I have been researching chia and other seeds for many years, since 2007. At that time there were many myths associated with ancient stories about these foods. To know whether what was said was true or credible in the scientific community, it had to be studied. In that sense, this has been our job to analyze the structure and microstructure of the seed, study its internal components and its macro and micronutrients, the mechanism by which mucilage is generated when the seed is put in water, etc. Subsequently, we studied the components separately, such as lipids, proteins, and fiber (soluble and insoluble), dedicating ourselves to evaluating how each of these components has effects on health and whether this effect occurs when consuming whole seed or as a separate supplement, among other things.
Loreto Muñoz: Two studies were carried out in animal models, specifically in mice, based on a model of prevention and reversal of diseases related mainly to fatty liver.
For this purpose, male mice were divided into 3 different groups: a control group received a normal diet, the second group received a high-fat diet and the third group received a high-fat diet with 20% chia seed flour over a 12-week period.
The high-fat diet, as expected, induced metabolic alterations and significantly reduced the production of short-chain fatty acids (CFAs). In contrast, the diet supplemented with the fiber-rich fraction exerted a protective effect by improving biochemical and hepatic parameters. In addition, these interventions led to an increase in the levels of polyunsaturated fatty acids (PUFAs) and Omega-3 in tissues and short-chain fatty acids (CFAs) in feces. Therefore, supplementation with fiber-rich fractions of chia seeds had a positive impact on biochemical parameters, hepatic steatosis, and fatty acid profiles. These findings suggest that the fiber present in chia seeds has therapeutic potential and maybe a tool to improve various parameters associated with metabolic syndrome.
Loreto Muñoz: This particular study is very relevant. When we consider their focus on prevention and reversal, we observe that when we incorporate fiber-rich flours or chia fiber itself, they can help decrease some major markers associated with Metabolic Syndrome, which contributes to direct improvements in health.
In detail, the results obtained indicate improvements in the hepatic markers of steatosis, (observed in the histological sections of livers), improves hepatic GAD, and liver cholesterol.
It is important to consider that when extracting chia oil, is done by cold pressing, chia flour/fiber maintains approximately 10% oil, of which 5% to 6% corresponds to Omega-3. This small amount of Omega-3 combined with dietary fiber, contributed to improve the lipid profile and parameters of oxidative stress and inflammation.
Chia seed has a very high percentage of fiber, which exceeds 50% of its composition. In fact, in an article we just published in Foods magazine, we analyzed the composition of eight different chia seeds in Latin America, including the black and white of Benexia. The seeds came from Mexico, Paraguay, Ecuador, Argentina, Peru, and Bolivia, among others. The study showed that the seeds have different compositions. This is why we always talk about a range of nutrients because depending on the origin, the components change.
The seed has two types of fibers: soluble and insoluble. Insoluble fiber helps digestion, but soluble fiber has a much more interesting particularity. What does soluble fiber do? When consumed, this type of fiber has the ability to absorb a lot of water, about 30 times its weight in water. What does that mean? It can mean several things: i) that by absorbing so much water, this fiber will occupy a large space in the stomach which can increase the feeling of satiety. ii) this soluble fiber is fermented in the large intestine, which improves the profile of beneficial microorganisms and the concentration of AGCCs; iii) on the other hand, the soluble fiber maintains its physical structure along the gastrointestinal tract, which implies that by consuming it you can trap fats, cholesterol or sugar within other critical nutrients which can be excreted by the feces.
In one study we observed that fiber has the ability to trap, and keep cholesterol retained until the end of digestion, that is, it enters and leaves our body. The same goes for glucose. Those are some of the features that differentiate chia fiber from other soluble fibers. In the case of other fibers, digestive enzymes, and stomach pH - close to 2 - are so strong that they lose their structure along the gastrointestinal tract. Chia fiber, on the other hand, maintains its viscosity, encapsulating nutrients that could be critical.
In summary, chia fiber stands out for its ability to absorb water and form a structure that traps harmful nutrients such as cholesterol and glucose, and then keep them encapsulated until excreted. This makes it promising to improve cardiovascular health and contribute to good blood glucose levels.
The outer layer of the seed called the testa, consists of three layers of mucilaginous cells. When the seed is put in water, a gelatinous substance known as mucilage surrounds the seed. Looking at it under the microscope, we can see a filamentous, three-dimensional structure, similar to a sponge. All the mucilage that surrounds the seed is the soluble fiber that traps water and/or organic molecules, such as fat, through its "activation" which is achieved by hydrating it.
Therefore, it is advisable to always consume chia fiber with a lot of liquid, because the formation of mucilage is activated in contact with water. It is ideal to hydrate chia for at least half an hour before consuming it to enhance its properties.
Loreto Muñoz: In about 30 minutes you have the mucilage hydrated. We did the lab test and realized that it takes about 2 hours to fully hydrate. In that time the mucilage is completely out of the test. However, it is not necessarily the ideal time, since in thirty minutes it is sufficiently separated to obtain the same effect.
Consider that there are liquids in the stomach and the food takes about two hours to process, which gives you enough time for activation to occur within your body.
Chia fiber can be hydrated in various liquids, such as milk, water, juices, soups, and smoothies. It can also be added in a food matrix such as yogurt, cookies, pasta, etc. In that case, it is recommended to take water to ensure that the fiber is activated correctly.
Loreto Muñoz:There are worldwide recommendations for dietary fiber intake. The World Health Organization (WHO) and other international health and nutrition agencies recommend a consumption of 25 to 30 grams of fiber per day. Hence, 100 grams of chia fiber exceeds these recommendations. Generally speaking, if you are looking for healthy effects, around 30 grams of chia a day is recommended. However, there are several factors to consider in order to achieve the desired results of prevention. One is that the effect is related to the amount of critical nutrients. For example, if you consume a spoonful of chia in water along with a spoonful of mayonnaise, which we know contains cholesterol, it will depend on the proportion. Mucilage has a limited ability to trap fats. Consequently, if you consume more cholesterol than mucilage, your body will still process cholesterol.
Loreto Muñoz: Any patient who is diagnosed with metabolic syndrome is a vascular risk patient. This risk is directly related to multiple factors, but one of the most important is food. Although there are genetic conditions, alcohol consumption, sedentarism, and others, much of this risk is directly related to diet.
In this context, fiber, and particularly chia fiber intake, contributes greatly. In the search for new sources of fiber, chia appears as the protagonist. Its properties can help prevent such diseases. The results of our study have shown that the fiber of chia seeds not only traps cholesterol and glucose but also free fatty acids and triglycerides, preventing these fats from being absorbed and causing cardiovascular problems.
Loreto Muñoz: Dietary fiber has been recognized in the last decade for its real importance, not only in Chile but worldwide. People in Africa consume more dietary fiber than we do, but access to healthy eating is expensive.
What about fiber? There are many foods that have it, but it is unknown and that is one of the key points. It is important first the awareness of the population, that is, effective communication where people learn what foods are rich in dietary fiber and why it is essential to consume it. Second, is nutritional education. We have all been raised with a particular diet at home, so it is difficult to introduce new healthy foods into our diet.
Regarding chia seed, it is recognized as a functional food. In this sense, make the advantages of its use known and understand why our ancestors considered it as food and medicine. To this day there is no age restriction to start consuming chia, nor for pregnant women or older adults. However, it is much better if it is incorporated from an early age, to build the consumption habit.
Loreto Muñoz: Yes, another important issue is the effect of chia soluble fiber on the microbiota and intestinal health. In another study we conducted, also published, where mucilage was used as a food matrix, it was observed that the fiber of chia has a prebiotic effect. Today there are many prebiotic products, which are mainly soluble fibers, which can be used by the gut microbiota, generating short-chain fatty acids. In our study, chia fiber, in addition to the prebiotic effect, inhibited the growth of pathogens and modified the pH of the large intestine, which can help recover the intestinal membrane, mucus and intestinal permeability.
1The study corresponds to a Fondecyt Project (1201489) led by Dr. Loreto Muñoz of the Central University of Chile in collaboration with Dr. Rodrigo Valenzuela of the University of Chile, which gave rise to a Master’s thesis in Nutrition entitled "Effect of fiber-rich chia seed flour intake on reversing hepatic steatosis and other metabolic alterations induced by a high-fat diet in mice" developed by student Camila Cisternas. It is not yet public, publication is expected by November 2023.
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