Abstract: Dietary fats are highly beneficial for satiety, maintaining energy levels, and keeping blood sugar balanced. Fat is needed for the proper absorption of a few critical pregnancy vitamins and minerals, including vitamin A and choline. Consuming enough fat during pregnancy is important for proper fetal development, particularly the omega 3 fatty acid DHA and its impact on fetal brain development. Dietary fat intake is essential. But the type of fat consumed is the most important. Learn about all the various types below!
What is dietary fat? What are the different types of fat?
Fats are the most energy-dense macronutrient, providing nine calories in every gram of fat. A major source of energy for the body, fat also aids in the absorption of fat-soluble vitamins A, D, E, K, and other food components, such as carotenoids. Fatty acids function in cell signaling and alter the expression of specific genes involved in lipid and carbohydrate metabolism. Dietary fat is the best for maintaining steady energy levels and balanced blood sugar, which subsequently leads to stable moods and curbing anxiety.
Dietary fat is absorbed in the intestine with the help of pancreatic enzymes and bile salts. Following absorption, the fats are reassembled into chylomicrons as they enter the body’s circulation. If they aren’t used by the body right away, they are taken up by adipose tissue and formatted for storage. When fat is needed for fuel, free fatty acids from the liver and muscle are released into circulation to be taken up by various tissues, where they are oxidized to provide energy.
Often considered the healthy fats, unsaturated fats can help reduce bad cholesterol levels in your blood and provide nutrients to help develop and maintain your body’s cells. They are mostly liquid at room temperature.
Monounsaturated Fats: A type of unsaturated fat with one double bond in its chemical structure, monounsaturated fats are found in avocados, nuts, seeds, and olive oil.
Polyunsaturated Fats: These fats have more than one unsaturated carbon bond and include essential fats that your body needs but can’t produce itself, such as omega-6 and omega-3 fatty acids, that must be obtained from food.
Omega-6 Fatty Acids: These fatty acids work to control your blood sugar and reduce your risk for diabetes. Even though they are important in their own right, omega-6 fatty acids are often easily obtained in the diet. The closer the omega 6 to omega 3 ratio of fatty acids consumed is to 1:1, the healthier the diet. This is why more emphasis is often given to consuming the more rare omega 3 fatty acids rather than omega 6 fatty acids.
Omega-3 Fatty Acids: These fats are an integral part of cell membranes throughout the body. Omega 3 fatty acids are essential fatty acids that the body needs for brain function and cell growth. They provide the starting point for making hormones that regulate blood clotting, contraction and relaxation of artery walls, and inflammation. They also contribute to the regulation of genetic function.
Saturated fats are a controversial fat that is associated with raised LDL cholesterol levels and should be limited. However, they are not as bad as we were once told. Even if saturated fats are associated with increased LDL cholesterol levels, the density of the LDL particles is the most important measurement, impacting risk of heart disease and stroke the most. Small density LDL particles are the most problematic. Furthermore, avoiding saturated fats to only consume more processed carbohydrates and sugars is not going to improve lipid profiles and heart disease risk. Saturated fats are beneficial in that they are a good source of energy and contribute to the structural components of cell membranes, enabling the normal functioning of proteins.
Man-made trans fats do not have a beneficial role in the body. They are bad and unhealthy. Trans fats directly raise your bad LDL cholesterol levels and lower your good HDL cholesterol levels. Eating trans fats increases your risk of developing heart disease and stroke.
Why is fat important during pregnancy? What types are the most important?
Numerous studies have documented the importance of proper nutrition during pregnancy. Both under and over nutrition in utero and during the first two years of life greatly influences an individual’s predisposition to obesity and other metabolic diseases. A recent study demonstrated that the types of fatty acids consumed during pregnancy play an important role in normal fetal and postnatal development. Excessive saturated fatty acids and trans-fatty acids induce harmful metabolic changes including insulin resistance, whereas polyunsaturated fatty acids show beneficial physiological effects.
Your body’s need for fat-soluble vitamins and other nutrients, particularly vitamin A and choline, goes up during pregnancy. Furthermore, brain-building and development are very demanding of fat. Because the brain is predominantly made of fat, almost all of its structures and functions have a crucial dependency upon essential fatty acids, which we get directly from our food. Unless excessive weight gain is a concern, limiting fat or cholesterol while pregnant is not advised. However, the quality of fat consumed is highly important. A diet high in soybean oil, which is all omega-6 fatty acids, is an entirely different story than one with a combination of fats that provides a balance of saturated, monounsaturated, and omega-3 fats, with low levels of omega 6 fats. The first diet will most likely result in adverse health effects including excessive weight gain and high blood sugar. The second diet, which incorporates various kinds of fat, will see healthful effects of balanced blood sugar, lower insulin, healthier liver function, and steady weight.
Fats from unprocessed real foods, including saturated fats found in meat and dairy, are an important source of nutrients during pregnancy. Inflammatory and common omega 6 fatty acids, found in vegetable oils, should be limited, in order to keep a more balanced omega 6 to omega 3 fatty acid ratio. Man-made trans fats should be avoided at all costs.
The Most Important Fat: DHA
One type of omega 3 fatty acid, DHA is especially important during pregnancy. DHA is a major component of the brain and retina and is needed for proper brain growth and eye development in fetuses and young babies. Getting enough of this vital brain-baby fuel in your diet is especially important in the last trimester when fetal brain development occurs at a rapid pace. Getting enough DHA also reduces the chances of your baby being born too early and at low birth weight.
What is the Omega6: Omega3 Ratio?
The omega 6 to omega 3 ratio is a measurement used to encourage the consumption of quality fats. The ideal ratio of omega 6 to omega 3 fats in the diet is somewhere from 1:1 to 4:1. Particularly during pregnancy, omega 6 fatty acids in high amounts can cause negative results and health complications, including preterm labor, abnormal fetal brain development, and metabolic health disruptions. Children of mothers who ate the most omega 6 fats during pregnancy were more likely to be overweight and have excess body fat. Women with a higher omega 6 to omega 3 ratio in their diet are 2.5x more likely to suffer from postpartum depression. Too many dietary omega 6 fatty acids also inhibit the synthesis of healthful DHA in the body, since omega 6 fats compete with omega 3 fats within the body preventing enough brain-boosting DHA from getting to the developing baby. Consequently, infants of women with a high omega 6 to omega 3 ratio in their diets are twice as likely to experience developmental delays.
To obtain an ideal ratio it is best to limit your consumption of processed vegetable oils. These include soy, canola, cottonseed, safflower, peanut, and corn oils found in many processed foods. Since these oils are cheaper, they are also used more readily in restaurants. Aim to cook more meals at home.
Why Are Trans Fats So Harmful?
Man-made trans fats are foreign to the human body and consequently disrupt a number of normal bodily processes. These fats are linked to diabetes and cardiovascular disease and strongly interfere with nutrient transport across the placenta making it harder for you to give adequate amounts of all those crucial pregnancy vitamins to your baby!
How Much Fat Is Needed?
Dietary guidelines from the World Health Organization and the Dietary Reference Intakes recommend a total fat intake of between 20% and 35% of total calories. The minimum of 20% is to ensure adequate consumption of total energy, essential fatty acids, and fat-soluble vitamins. The minimum also ensures a healthy lipid profile, combating low levels of HDL and high triglycerides, which can occur with low-fat, high carbohydrate diets. The maximum of 35% was based on limiting saturated fat and also the observation that individuals on higher-fat diets consume more calories, resulting in weight gain. The 2015 Dietary Guidelines Advisory Committee emphasizes the types and quality of foods consumed and avoids setting an upper limit for total fat due to a lack of evidence of resulting adverse events.
|Fat Type||% of Total Calories|
What are some dietary sources of the various types of fat?
Unsaturated Fat Food Sources
Unsaturated fat food sources include various plant oils, such as vegetables, olive, canola, avocado, walnut, and sesame. Other sources include avocados and nuts (almonds, hazelnuts, and pecans). Polyunsaturated fat food sources, particularly those high in DHA, include salmon, sardines, canned tuna, walnuts, brazil nuts, pumpkin seeds, sunflower seeds, chia seeds, flax seeds, seaweed, and eggs.
Saturated Fat Food Sources
Saturated fat can be found in mostly animal-based foods, such as beef, lamb, pork, poultry, butter, cheese, ice cream, coconut, coconut oil, palm oil, and some baked and fried foods.
Trans Fat Food Sources
Trans fat can be found in foods containing partially hydrogenated oils, such as shortening, margarine, fried foods, fast foods, doughnuts, cakes, store-bought frosting, cookies, and pastries.
What are the risks of inadequate intake?
Inadequate intake of dietary fat may result in impaired growth and an increased risk of chronic disease. Fat restriction is particularly concerning during infancy, childhood, and pregnancy since these are relatively high energy phases for both energy expenditure and fetal development. Low fat and high carbohydrate diets are harmful to metabolic health, reducing good HDL cholesterol levels and increasing serum triglyceride concentrations, ultimately increasing the risk of chronic diseases such as coronary heart disease and diabetes.
What about overconsumption of fats?
There is no defined level of fat intake at which an adverse effect, such as obesity, can occur. Weight gain is dependent on many factors including exercise and genetics. High-fat diets in excess of energy needs can cause obesity and are associated with increased risks of heart disease, cancer, and insulin resistance. However, the type of fatty acid consumed is very important in defining these associations.
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