Nutrition Science and Everyday Application - beta v 0.1

254 ALICE CALLAHAN, PHD, HEATHER LEONARD, MED, RDN, AND TAMBERLY POWELL, MS, RDN
Figure 5.4. There are two types of fat stored as adipose tissue: subcutaneous fat and
visceral fat.
Regulating and Signaling
Fats help the body to produce and regulate hormones. For example, adipose tissue secretes
the hormone leptin, which signals the body’s energy status and helps to regulate appetite.
Fat is also required for reproductive health; a woman who lacks adequate amounts may
stop menstruating and be unable to conceive until her body can store more energy as fat.
Omega-3 and omega-6 essential fatty acids help regulate cholesterol and blood clotting
and control inflammation in the joints, tissues, and bloodstream. Fats also play important
functional roles in sustaining nerve impulse transmission, memory storage, and tissue
structure. Lipids are especially focal to brain activity in structure and in function, helping
to form nerve cell membranes, insulate neurons, and facilitate the signaling of electrical
impulses throughout the brain.
THE FUNCTION OF FATS IN THE DIET
Aiding Absorption and Increasing Bioavailability
The dietary fats in the foods we eat aid in the transport of fat-soluble vitamins, carrying
them through the digestive process and improving their intestinal absorption. This improved
absorption is known as increased bioavailability. Dietary fats can also increase the
bioavailability of compounds known as phytochemicals—non-essential plant compounds
considered beneficial to human health. Many phytochemicals are fat-soluble, such as
lycopene found in tomatoes and beta-carotene found in carrots, so dietary fat improves the
absorption of these molecules in the digestive tract.