The Macronutrients

The use of foods by organisms is termed nutrition. The ability of an organism to use a particular food material depends upon its chemical composition and upon the metabolic pathways available to the organism. In addition to essential fiber, food includes the macronutrients—protein, carbohydrate, and lipid—and the micronutrients—including vitamins and minerals. 

Polymeric formulas typically have low osmolality of 300 to 500 mOsm/kg. These formulas also usually supply essential vitamins and minerals in amounts similar to the Adequate Intakes or Recommended Dietary Allowances for these nutrients when the formula is delivered in amounts adequate to meet the macronutrient requirements of most patients. Many polymeric formulas are inexpensive relative to oligomeric formulas. Most polymeric formulas are lactose-free and gluten-free, as are most modern tube feeding products. Products designed to be used as oral supplements generally are polymeric and often have sucrose or other simple sugars added to improve taste. 

No significant quantity of the macronutrients nor of the vitamins for which U.S. Recommended Dietary Allowance (RDA) have been established can be obtained from the consumption of a cup of tea.110 The water-soluble B vitamins present are easily extractable. Eight percent extractabil-ity for a representative black tea blend is assumed.110... 

The level of plant mineral nutrients available to trees is known to affect fruit quality, but its relative effect is often overestimated compared to other factors such as fruit load and light (and associated assimilate supply to fruit) (see sections above) (for review see Neilsen and Neilsen, 2003). The mineral nutrition of trees and fruits is complex. Uptake of the macronutrients nitrogen... 

Patient case A patient s daily nutritional requirements have been estimated to be 100 g protein and 2,000 total kcal. The patient has a central venous access and reports no history of hyperlipidemia or egg allergy. The patient is not fluid restricted. The PN solution will be compounded as an individualized regimen using a single-bag, 24-hour infusion of a 2-in-1 solution with intravenous fat emulsion (IVFE) piggybacked into the PN infusion line. Determine the total PN volume and administration rate by calculating the macronutrient stock solution volumes required to provide the desired daily nutrients. The stock solutions used to compound this regimen are 10% crystalline amino acids (CAA), 70% dextrose, and 20% IVFE. 

Micronutrients Elements or compounds (like iron, other trace metals, and vitamins) that are necessary to sustain life and that are present in smaller amounts than the macronutrients (see above). 

Trace metals are resolubilized from the biogenic hard and soft parts in much the same way as the macronutrients. Thus, the depth profiles of the trace metals with high EFs tend to be similar in shape to those of the nutrients. Efforts have been made to develop a Redfield-Richards type ratio far the trace metals in marine plankton. Surprisingly, field and lab work suggests that a relatively constant composition can be defined for whole... 

Although it is usually considered that mastication and digestion are the first processes in the conversion of food into suitable components to be absorbed by the body, cooking of food is also very important it makes the macronutrients and micronutrients more readily available for... 

Nutrients are the constituents of food necessary to sustain the normal functions of the body. All energy is provided by three classes of nutrients fefe, carbohydrates, protein, and in some diets, ethanol (Figure 27.1). The intake of these energy-rich molecules is larger than that of the other dietary nutrients. Therefore, they are called the macronutrients. This chapter focuses on the kinds and amounts of macronutrients that are needed to maintain optimal health and prevent chronic disease in adults. Those nutrients needed in lesser amounts, such as vitamins and minerals, are called the micronutrients, and are considered in Chapter 28. 

The energy generated by metabolism of the macronutrients is used for three energy-requiring processes that occur in the body resting metabolic rate, thermic effect of food (formerly termed specific dynamic action), and physical activity. 

Total caloric consumption and distribution of calories between the macronutrients in adults. 

Key concept map for the macronutrients. Note Trans fatty acids are chemically classified as monounsaturated... 

Human milk can be considered the optimal food for infants. It contains all the macronutrients and micronutrients necessary for the correct development of the newborn and at the adequate levels. When infants are not breast-fed, or breastfeeding is discontinued very early, formula milks are used instead. Therefore, it is important to evaluate the capacity of formulas to deliver satisfactory quantities of minerals and trace elements that can be bioavailable to the children in order to cover their biological needs. This fact explains the need to perform trace elements speciation analysis in formula milk. Thus, the speciation results obtained in formulas and published so far are critically evaluated here and compared with those obtained in human milk. 

All microorganisms require varying amounts of a large number of nutrients. These are required because they are necessary components of bacterial protoplasm. The nutrients can be divided into three groups macro, minor, and micro. The macronutrients are those that comprise most of the biomass. These are given by the commonly accepted formula for biomass (Cml 2I ). The carbon, hydro-... 

Consideration of the macronutrients in various animal diets, their isotopic compositions, and the pathways by which they are utilized in the body, lead us to conclude that different models... 

The macronutrient-rich surface waters of the equatorial upwehings and polar oceans are a particularly dynamic component of the global carbon cycle. In the Southern Ocean, for example, the nutrient-rich and C02-charged waters of the deep sea are exposed to the atmosphere and returned to the subsurface before the available nutrients are fuUy utilized by phytoplankton for carbon fixation. This incomplete utilization of upweUed nutrients aUows for the leakage of biologicaUy sequestered... 

The overall consequence of the co-evolution of oxygenic photosynthesis and the redox state of the ocean is a relatively well-defined trace-element composition of the bulk phytoplankton. Analogous to Redfield s relationship between the macronutrients, trace-element analyses of phytoplankton reveals a relation for trace elements normahzed to cell phosphorus of (C125N16P1S13... 

They differ from micronutrients by the quantities required according to nutritional guidelines, daily macronutrient intake for an adult should include 130 grams of carbohydrates, about 50 grams of protein, 40 grams of fat, and 30 grams of fiber. All of the macronutrients featured in the following sections are considered essential for health and are present in all plant foods and superfruits in different amounts. 

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