| 影響 | Why is fats important?
Our health is something we can influence by the way we live. Our lifestyle – what we eat, drink, the amount of physical exercise we take and our outlook on life are some of the most important health factors under our control. Much research has been done in recent years to show how food components such as vitamins, minerals, fats, and dietary fibre affect our health. Science has now shown that a healthy diet can help protect us against some of today’s most common diseases, including heart disease, arthritis, cataracts, some forms of cancer, and may possibly delay aging.
Fats which contain many different kinds of fatty acids are involved in a wide variety of body functions. Their most obvious is to store energy until it is needed. They also influence the flavour and texture of foods and make it possible to absorb the fat soluble vitamins A, D, E and K. Fats contain many different kinds of fatty acids that are involved in a wide variety of body functions.
Every cell in the body is enclosed in a membrane that helps keep the contents of the cell together, maintains its shape and flexibility, and controls the passage of substances into and out of the cell. The physical properties of the membranes are strongly influenced by the fatty acids involved. In some membranes, such as those in the skin and in the protective sheath around nerves, specific fatty acids provide a water barrier and insulating layer.
Some fatty acids in cell membranes are required for the production of chemical messengers that initiate or control numerous processes in the body. These include cell growth and division, blood pressure and blood coagulation, immune reactions and tissue inflammation.
What are Polyunsaturated Fatties?
Fatty acids have a ‘chain’ like structure. They differ from each other in the length of the chain, and in the number and position of the “rigid” links (double bonds). When all the links are flexible, the fatty acid is said to be “saturated”. Fatty acids with one rigid link or double bond are called “monounsaturated”, and those with more than one double bond are “polyunsaturated”.
Monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) can be further divided into special “families” according to the position of the double bond on the chain. Each family is distinct from the others. The three most important families in human health have the first double bond at the 3rd, 6th and 9th position and are known as omega-3, omega-6 and omega-9 fatty acids.
Generally you don’t need to worry about whether you eat enough of any particular fatty acid as your body can make enough of any particular fatty acid. However, two PUFAs (linoleic and alpha-linolenic acid) cannot be produced in the body and, like vitamins, have to be obtained either from food or supplements. These PUFAs are called “essential fatty acids”. |
