Apart from the food groups, our body also needs essential nutrients. These should be contained in the food that we eat. In fact, the reason why food is split into food groups represented in the pyramid is to try to ensure that you give your body these essential nutrients.
Nutrients that are needed in relatively large quantities are called macronutrients. Those nutrients that are needed in relatively small quantities are called micronutrients.
There are seven main kinds of nutrients that your body needs – those are carbohydrates, proteins, fats, vitamins, minerals, fiber and water. It is important to consume these seven nutrients on a daily basis to build and maintain health.
Carbohydrates may be classified as monosaccharides, disaccharides, or polysaccharides depending on the number of sugar units they contain. Monosaccharides contain one sugar unit, disaccharides contain two, and polysaccharides three or more.
The difference between these kinds of carbohydrates is important to nutritionists since complex carbohydrates take longer to metabolize. This is because their sugar units are processed one-by-one off the ends of the chains of which they are made up.
Simple carbohydrates are metabolized much more quickly and raise blood sugar levels more rapidly resulting in rapid increases in blood insulin levels. Monosaccharides and disaccharides are simple sugars that are found in refined sugars, like white sugar. But they are also found in healthier options such as milk or fruit, which also contain vitamins, fiber, and important nutrients like calcium.
Polysaccharides, also known as complex sugars, include the carbohydrates that are also known as starches. Starches include grain products including bread, crackers, pasta, and rice. Some complex sugars are better health choices than others.
Refined grains like white flour and white rice which have been processed are not beneficial because much of the nutrients and fibers that have been removed during the refining process.
Unrefined grains still contain these vitamins and minerals. Unrefined grains are also very rich in fiber, which helps the digestive system work well, and helps us feel full so we are less likely to over-eat.
When we eat carbohydrates, the body breaks them down into simple sugars. These sugars are then absorbed into the bloodstream, and as the sugar level rises in your body the pancreas creates and releases a hormone called insulin. Insulin is what is needed to move sugar from the blood into the cells of the body where the sugar can be used as a source of energy.
In the case of simple sugars, this process takes place very quickly and you are more likely to feel hungry again soon. In the case of complex sugars, the process takes much longer and so these kinds of carbohydrates give energy for a longer period of time.
Protein is made up of amino acids. These are the body’s structural (muscles, skin, hair etc.) materials. Our organs and immune system are made up mostly of protein.
The digestive juices in the stomach and intestine break down the proteins in the food matter that we consume into the basic constituent units, which are the amino acids. These amino acids are then used to make the human proteins that our body needs to maintain our muscles, bones, and blood and body organs.
The body also needs amino acids to produce new body protein and to replace damaged proteins that are lost in the urine.
Many foods contain protein but the best sources of protein are beef, poultry, fish, eggs, dairy products, nuts, seeds, and legumes such as peas and beans. Our body uses the protein we consume to make lots of specialized protein molecules that have specific jobs. For example, our body uses protein to make hemoglobin – the red cells in the blood. Other proteins are used to build cardiac muscle, for example.
There are many different kinds of proteins but there are twenty two essential for your health. Thirteen of these are produced by the body, whilst the rest are obtained from the food we consume.
Proteins are made up of amino acids, eight of which are essential and they are all provided in animal protein. Fish, poultry and meat are the main animal protein foods. Dairy produce, such as eggs, cheese and milk, is also a source.
Plant sources of protein do not include all the essential amino acids in any one food, with the exception of soya beans, which are a source of high-quality protein. Other beans and pulses, rice and grains provide protein. When a good mix of vegetable foods is eaten, the body obtains all the amino acids it needs.
Fats are made up of fatty acids. Most fatty acids are non-essential, which means that the body can produce them as and when they are needed. However, at least two fatty acids are essential and must be consumed in the diet. These are omega-3 and omega-6.
Animal fats tend to have higher content of saturated fat than vegetable fats. The amount of fat in the diet should be limited to a small amount daily and the majority of the fat we eat should be unsaturated. High-fat foods, such as butter, cheese, cream, fatty meats, oils and oil-based spreads and dressings, should be used in modest amounts.
Unsaturated fats are found in plant foods and fish and these are good for the heart. The best of the unsaturated fats are found in olive oil, peanut oil, canola oil, albacore tuna, and salmon. Oily fish should be eaten regularly – ideally twice a week – to provide the valuable omega-3 and fatty acids.
Dietary fibers are the indigestible portion of plants eaten as food that move the food through your digestive system. They absorb water thus making digestion and ultimately defecation easier. Dietary fiber is made up of non-starch polysaccharides such as cellulose. Dietary fiber is found in fruit, vegetables, whole grains and legumes. On a day to day basis, fiber provides the bulk of your intestinal contents.
More than 70% of the mass in the human body that is not fat is made up of water. To function well, our body needs anywhere between one and seven liters of water a day to avoid dehydration.
The amount needed by each person depends on the level of physical activity, temperature, humidity and other external factors. With increased exertion and exposure to heat, the amount of water lost will increase and you will need to increase the amount of daily fluid intake.
Usually around 20% of the water intake comes from food, while the rest will come from drinking water and other kinds of beverages including caffeinated ones. Water is lost from the body through feces, sweating and the exhalation of water vapor in your breath.
An antioxidant is a molecule that can slow down or prevent the oxidation of other molecules. Oxidation reactions can produce free radicals, which start chain reactions that damage other cells.
Some antioxidants are produced by the body and those that the body cannot produce can only be obtained through the diet from direct sources (Vitamins C, A and K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D from cholesterol by sunlight).
Phytochemicals are a relatively new subject of interest to those who study human health. These are antioxidant nutrients found in edible plants, especially colorful fruits and vegetables. They are also found in high quantities in organisms such as seafood, algae and fungi such as edible mushrooms.
One of the main classes of phytochemicals are polyphenol antioxidants, which have been proven to provide health benefits to the cardiovascular system and the immune system.