Carbohydrates and fiber in cardiovascular diseases

Carbohydrates

Carbohydrates (also called carbohydrates or carbohydrates or sugars) are a very important source of energy from food. All tissues use carbohydrates (in the form of glucose) to obtain the immediate energy they need, although they can also use other nutrients such as fats or even proteins.

There are different types of carbohydrates, from the simplest (a basic structural unit called monosaccharide) such as glucose, to the most complex (union of many simple carbohydrates) such as glycogen from animals or starch and cellulose from plants.

Food sources of carbohydrates are varied and can come from both the plant and animal kingdoms. However, the vast majority of the carbohydrates we consume (starch) come from vegetables: cereals, legumes, fruits, vegetables and greens. Simple carbohydrates come from bakery products, candies, etc. Among the animal products that are a source of carbohydrates (glycogen and simple carbohydrates), milk and its derivatives stand out. The cellulose that we have referred to before as a complex carbohydrate is not a food source for humans because it is not digestible, but it is useful for obtaining fiber.

We can also classify carbohydrates according to the processing method as: whole, and refined or processed. In this classification we refer basically to the carbohydrates contained in grains. Whole grains are those that contain the whole grain, including the husk. In the refining process, the cereals are ground, which removes the seed and the husk. With this, a finer texture is achieved (they are easier to digest) and they are less perishable, but in the process they lose fiber and many substances such as vitamins, minerals and antioxidants.

From a strictly nutritional point of view we can also include as refined foods that contain simple carbohydrates (sugars); These compounds provide calories, but lack vitamins, minerals, and fiber, which is why they are called "empty calories." An increase in its intake affects blood fats (increases triglycerides and lowers HDL cholesterol), produces spikes in blood sugar due to the rapid absorption of this sugar, helps the development of overweight and obesity, and increases cardiovascular risk.

On the other hand, at the opposite extreme are complex carbohydrates (in whole grains and legumes), which cause a slow and prolonged rise in blood sugar, do not modify blood fats, and have a beneficial effect on cardiovascular diseases.

Postprandial hyperglycemia (sugar spikes that occur with food or immediately after food) are a clear cardiovascular risk factor, regardless of whether the person is diabetic or not. Therefore, dietary recommendations to minimize this risk factor must be aimed at increasing the intake of complex carbohydrates (legumes and whole grains).

Vegetable fiber

The fiber called dietary or food is a set of substances of plant origin, mostly carbohydrates, resistant to breakdown by proteins (enzymes) that we have in the intestine to digest food. It is an important component of a diet abundant in foods of plant origin.

There are two different types of dietary fiber defined by their physical behavior in water: (1) insoluble fiber, such as cellulose, lignin and some hemicelluloses, abundant in whole grains; and (2) soluble fiber, such as gums, mucilages and pectins, contained mainly in legumes, vegetables and fruits, and beta-glucans present in oats, barley and some yeasts. A particular variety of soluble fiber is psyllium, obtained from the bark of a bush and used as a laxative (by increasing the fecal bolus) and as a cholesterol-lowering agent in patients with moderate hypercholesterolemia. Most plant products contain a mixture of soluble and insoluble fiber in a ratio of approximately 1: 3. However, oats (particularly oat bran), barley, legumes, apples, and citrus fruits contain higher amounts of soluble fiber, while wheat bran, bread, and whole grains mostly contain insoluble fiber.

In our diet, the main sources of fiber are vegetables, fruits, legumes and whole grains.

From a cardiovascular point of view, diets rich in fiber reduce the risk of suffering from cardiovascular disease or dying from it. An inverse relationship between fiber intake and the incidence of diabetes mellitus has also been shown in several epidemiological studies. It should be noted that fiber from cereals and fruits has a protective effect on cardiovascular disease, but this effect has not been observed with the fiber ingested with vegetables.

Soluble fiber exerts its cardiovascular risk-reducing effect by several mechanisms: it reduces blood cholesterol, lowers blood pressure figures, prevents blood clotting and reduces the peaks in sugar and insulin that occur with food intake. . The improvement in the figures for these parameters achieved by fiber is, however, modest. Soluble fiber also helps you lose weight and keep it off.

Insoluble fiber does not have (or at least has not been demonstrated) these effects on risk factors for cardiovascular disease such as cholesterol, blood pressure or insulin and blood sugar spikes. However, insoluble fiber produces a much lower incidence of cardiovascular disease and diabetes mellitus than soluble fiber.

Based on these data, we can establish the following recommendations on fiber consumption to maintain good cardiovascular health: in adults (over 18 years of age) an intake of about 25-35 g / day is recommended, with a ratio of insoluble fiber and soluble 3: 1. These recommendations correspond to caloric intake: 10-13 g of fiber for every 1,000 kcal ingested. And we must obtain it from varied foods. In children over 2 years of age, a fiber intake is recommended according to the rule "age + 5" grams / day; Thus, for example, a 3-year-old child should eat about 8 g of fiber per day. This corresponds to a daily intake of 0.5 g of fiber / kg of the child's weight. The clear need for fiber in children under 2 years of age has not been established.

The tips to get these figures are:

• Consume two to three servings of vegetables or salad a day.
• Eat nuts with some regularity, for example a "handful" (25 grams without shell) between two and three times a week. If possible, take them with the edible peel.
• Incorporate cereals and derivatives into the diet, preferably whole grains (whole seed) or enriched with fiber (bread, cookies, rice, pasta, breakfast cereals, etc.), at least two or three times a day.
• Consume two to three pieces of fruit a day, better whole than in juice. Let's not forget that the pulp, richer in fiber, stays in the juicer. On the market there are fruit juices rich in fiber, which can be consumed.
• Consume legumes (beans, chickpeas, lentils, etc.) at least twice a week.

Remember that ensuring water intake is very important when the diet is rich in fiber. You have to ensure the intake of at least 2 liters of water a day.

In addition, it must be taken into account that the increase in fiber in the diet must be gradual to avoid the symptoms of flatulence and intestinal discomfort that fiber can produce.