Whole grain cereals consumption

Thiamine is, like some other vitamins, produced by intestinal microflora. The level of vitamin delivered in this way is too low, so in practice the required amount is only obtained through food. The most important sources of thiamine are whole grain cereal products that supply about 40% of the vitamin requirements (bread covers about 20%). Other important sources are meat and meat products (18 27%), milk and dairy products (8 14%), potatoes (10%), legumes (for reasons of low consumption, about 5%), vegetables (up to 12%), fruits (about 4%) and eggs (about 2%). Other foods supply the requirements for this vitamin to a lesser extent. 

Currently, it is not possible to recommend a specific intake of fiber more research is needed. However, dramatic increases in dietary fiber should be avoided since the absorption of minerals may be reduced by high dietary fiber intakes. Moderate increases in the consumption of fiber can be easily achieved by increasing the consumption of nuts, vegetables, fruits, and whole grain cereal products. The fiber content of various foods is given in Food Composition Table F-21. 

Cereals and cereal products are not only the largest single source of energy, but also a main source of dietary iron. In many countries the iron content of bread made from white flour is therefore increased by fortifying the white flour with iron. But there is also another way to increase the iron content in the diet and that is to increase the consumption of whole grain flour. 

An increase in consumption of whole grain flour products is the nutritional aim in Norway. The high content of dietary fiber or factors associated with it, however, present in bran and whole grain flour, may interfere with the bioavailability of iron as indicated by several authors (2,3,4). Phosphate and especially phytic acid present in unrefined cereal products have frequently been said to be potent inhibitors of iron absorption (5,6). 

It has long been known that percent iron absorption is somewhat dependent upon the total amount of iron provided by the diet. Shifts in consumption patterns toward the eating of less red meats may result in actual increases in total iron contents-of such dietaries if replacement is made with whole-grain or enriched cereals however, if the replacement is in terms of milk or cheese, as is often the case with the lacto-vegetarian, the iron consumption may well decrease. 

There is no question that whole grains exert health benefits, but the American intake is about 20-30% of the cereal grain category. There is a long history of cardiovascular health benefits associated with the routine consumption of whole-grain products (Jacobs et al., 1998, 1999 Liu et al., 1999). Evidence of benefits of whole grains in diabetes has emerged (Liu et al., 2000). 

Koh-Banerjee, R, et al.. Changes in whole-grain, bran, and cereal fiber consumption in relation to 8-y weight gain among men. Am. J. Clin. Nutr. 80, 1237, 2004. 

Since the 1956 report by the U.S. Department of Agriculture (Table M-13), health and dietary professionals have urged the American people to (1) reduce the consumption of total fat, especially saturated fat and cholesterol (2) increase the intake of fruits, vegetables, and whole grain products and cereals and (3) increase the consumption offish, poultry prepared without skin, lean meats, and low-fat dairy products. Dietary changes have been made since 1956, but further improvements will lessen the risk of coronary heart disease. 

The use of bread and cereal intakes as a measure of total whole-grain consumption is of some concern, as the extent to which they correlate with overall whole-grain consumption is uncertain. Indeed, such studies also fail to distinguish whether it is in fact something within the whole-grain package that is of benefit, or something else entirely. 

The relationship between whole grains and diabetes has been studied in five large cohorts as highlighted in Table 3. All of the studies have found an inverse relationship between consumption of whole grains or cereal fiber and disease reduction despite slight variations in methodology. 

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