Determination of dietary essential nutrients often requires use of several methods, such as balance studies, growth studies, tissue saturation, or physiologic responses. Currently, molecular techniques are additionally able to help define the more detailed molecular features for both clinical and cellular nutrition. These methods and techniques comprise important tools for modern nutrition science.
Minimal and optimal nutrition currently encompasses nutrients (eg, phytonutrients, antioxidants, and fatty acids) heretofore not considered by early nutritionists. New standards are being used for evaluation of these nutrients physiologically or at the molecular and cellular levels. In this manner, minimum requirements can be understood both clinically
Modification of metabolic responses for cholesterol and other lipids as a result of dietary methods or drugs has been extensively studied in humans and laboratory animals, and much has been published on this topic. However, less is known about this topic in small companion animals, such as dogs and cats. One of the reasons is that compared to humans, cats and dogs are typically resistant to coronary artery disease, myocardial infarction, cerebral vascular stroke, and atherosclerosis. Thus, they are rarely studied in regard to these disorders. Nonetheless, dogs are especially useful in the evaluation of compounds that lead to important
Cats are unique among mammals with respect to metabolism of fatty acids. Except for some ruminants, all other mammals, including cats, are able to synthesize nonessential saturated and monounsaturated fatty acids de novo from glucose or amino acids via a common precursor, acetyl CoA. The products of this synthesis are 16- and 18-carbon saturated fatty acids that can subsequently be desaturated to monounsaturated fatty acids of the n-7 and n-9 fatty acid families (eg, 16:1n-7 and 18:1n-9). These acids are the result of the introduction of a single double bond between carbons Δ-9 and Δ-10 of the respective saturated acids.
Dietary fish oil treatment in humans has been traced back to 1783 when it was described as a treatment for rheumatism in the London Medical Journal. However, additional published information did not appear until 1914, when August Krogh and his wife visited Greenland Eskimos and studied their dietary habits.1 Subsequently, Heinbecker2 also studied the metabolism of Eskimos and referred to the work of the Kroghs', indicating that Eskimos eat almost only flesh and that all animals in the North are eaten by Eskimos but they depend mainly on those found in the sea.
In human health and nutrition, the concept of good fats and bad fats is typically used, especially with respect to dietary risk factors for coronary artery diseases and stroke. This concept originated with the notion that there are 2 forms of cholesterol that, for the sake of simplicity, have been referred to as good and bad. The concept has now been extended to include other dietary fats that may also be associated with increases in cholesterol concentrations.
Dietary fats, including cholesterol, are transported in the blood as lipoprotein complexes. They include LDLs and HDLs.1 Because LDL, which transports
The World Health Organization defines overweight and obesity as abnormal or excessive fat accumulation that may impair health. In dogs, overweight is considered the point at which body weight is > 15% over ideal body weight, whereas obesity is defined as the point at which body weight exceeds 30% over ideal body weight.1 There has been a dramatic increase in obesity in the United States during the past 2 decades. In 1 study,2 investigators conducted a survey in 1999 and 2000 to determine the prevalence of obesity for a diverse population of 4,115 adult men and