Agriculture Reference
In-Depth Information
Figure
2.8.
Protein, fat, mineral, and vitamin content of common carbohydrate sources. (Data
from Agricultural Research Service Nutrient Data Laboratory USDA National Nutrient Database
for Standard Reference, Release 17, http:
//
www.nal.usda.gov
/
fnic
/
foodcomp
/
Data
/
SR17
/
reports
/
sr17page.htm.)
substantially in the required energy component of a diet. In Figure 2.8 both maize and rice
are shown to have significantly more protein and fat than potato and cassava. None of the
carbohydrate sources have significant fat content. Cassava is maligned because it has high
carbohydrate content but low protein content. However, it is seen to have much higher
vitamin content, mostly vitamin C, than do the other carbohydrate sources. Also none
of these carbohydrate sources is a significant source of minerals.
In some parts of the world fats, oils, and refined foods are a significant source of energy.
Fats and oils have high energy content (see Table 2.2). Thus, if high-fat foods, such as fatty
meats (e.g., pork) or foods cooked in fats such as fried foods are consumed on a regular
basis, their fats and oils will provide significant kilocalories in the diet. Refined foods
are food items that have been significantly changed from their original form by removing
some of their components. This often means that vitamins, minerals, and fiber have been
removed. The resulting food is often easier to digest and has higher energy content.
While as an energy source they are better, overall they are often less nutritious.
2.4
PROTEIN AND AMINO ACIDS
Proteins, which are polymers of amino acids, make up the muscle of the body and are
responsible for all bodily movement including the heart and lungs, without which the
