There are many well-meaning people who, with a limited understanding of diet and the contribution of nutrients, aim to guide and advise people on the use and application of nutrients. This results in a misconception and thus misuse of supplements, etc, as people strive for optimum health.
Nutrients are required for energy production but they are not alone. Sugars and saturated fats also provide energy but have little nutritional value and the body must work hard to expel substances that are potentially harmful to health.
Nutrients do assist in the process of "synthesizing" substances but they have been found to do much more
revealing important interrelationships among nutrition, metabolism, and genotype
Biochemical reactions that take place upon the absorption of nutrients, contribute to health but a lack of and even excess nutrients contribute to disease
including birth defects, diabetes, cardiovascular disease, obesity, and certain cancers.
When a person craves certain nutrients, for example, a pregnant woman whose combinations of nutrients may leave others reeling and feeling rather nauseous themselves, the body is obviously trying to tell her something and hormones are also at play in this process.
Red meat has created contentious debate and its ability to provide nutrients such as
bioavailable iron and vitamin B12 or B6 not found in plant foods
cannot be disputed but it brings with it saturated fat, which is harmful when consumed to excess. Populations are painfully aware of the consequences of cardiovascular diseases, and therefore discount any nutirional value in foods like red meat.
It seems clear then that whilst the statement, "Nutrients are used for energy or to synthesize substances in the body after they are absorbed," is certainly true, it would be unwise to accept this as an absolute truth; nutrients can create far-reaching consequences, thus a responsible statement about nutrients that perhaps includes a warning would provide a better indication for those reading and considering it.