Nutrition - NCLEX-PN

In standard units, the formula for body mass index is:

Normal BMI is considered to be 18.5 - 24.9. A BMI below that would indicate that the individual is underweight, while a higher value may indicate that the individual is overweight.

BMI values between 30 and 39.9 indicate obesity, while a BMI over 40 could indicate that the individual is severely obese.

Vitamin B5, or pantothenic acid, is the only water-soluble vitamin listed. Vitamins A, E, D, and K are all fat soluble and so should be consumed with fat to be absorbed.

While all of the substances listed are present in gastric secretions and are necessary for normal digestion, intrinsic factor is the only one that has a direct role in vitamin B12 absorption in the small intestine. Deficiencies in intrinsic factor due to genetic variation or damage to stomach lining can result in pernicious anemia, a type of anemia that is caused by insufficient levels of B12.

The digestion of dietary carbohydrates is initiated by amylase, an enzyme present in saliva. This enzyme breaks down long carbohydrate molecules into shorter units such as disaccharides. Lipase breaks down fats and is not present in the saliva, rather it is secreted by the pancreas into the duodenum. Pepsin is a protease - an enzyme that breaks down proteins. This enzyme is secreted by the chief cells of the stomach in its zymogen form (pepsinogen). It is activated by the product of the parietal cells (hydrochloric acid). Note that amylase is also secreted by the pancreas to complete the chemical digestion of carbohydrates into monosaccharides so that they can be absorbed by the brush border of the small intestine.

Bile is produced exclusively in the liver. It may then be stored in the gall bladder so that it can be released during digestion of a fatty meal. No bile is produced in the stomach, nor the duodenum. The vast majority of bile is cholesterol-derivatives that stick to dietary fiber and are excreted along with the fiber. Thus increasing fiber is (mainly soluble) is an effective way to decrease cholesterol.

Allicin is found primarily in garlic, and has a variety of properties that are beneficial to the health. It is antimicrobial, anti-inflammatory, anti-thrombotic, it can reduce atherosclerosis, decrease blood pressure, and act as a mild antioxidant.

Half an ounce of ground flax seeds provides over 130% of the dietary reference intake (DRI) of omega 3 fatty acids. An equivalent serving of shrimp is able to provide 15% of the DRI. Wheat germ oil and grapeseed oil are both good sources of omega 6 fatty acids but are not significant sources of omega 3 fatty acids.

Capsaicin, found in cayenne peppers and other species of plants in the genus Capsicum, is used in topical analgesic creams to reduce joint and muscular pain. It is thought to work by depletion of substance P in the sensory nerves.

Manganese, found in oats, brown rice, chickpeas, and spinach, is a cofactor for the enzymes that produce the amino acid proline. Proline is essential for collagen shape and integrity, and is an amino acid, not a cofactor. Other important minerals required for collagen production include copper, zinc, vitamin C, and iron.

Children ages 1-18 are at the highest risk for physiological changes due to malnutrition. Significant nutritional deficiencies at this age can cause failure to thrive, stunted growth, long-term brain damage, and increased incidence of cardiovascular and metabolic disease later in life.

Prolonged laxative use can lead to hypokalemia and hypocalcemia. This is due to alterations in gastrointestinal absorption and excretion of potassium and calcium. Magnesium can also be depleted during long-term laxative use, but chromium is unlikely to be affected. Zinc, copper, manganese, and selenium are also not generally impacted by normal laxative use.

Dark leafy greens such as kale, collard greens, and chard have among the highest levels of vitamin K of any food. The other foods listed: beets, sweet potatoes, and pumpkin all have very low vitamin K content, and are safe for a patient on a warfarin diet.

Grapefruit can decrease the activity of cytochrome P450, one of the body's most important detoxification pathways, by as much as 30%. Consumption of grapefruit while on certain medications, including atorvastatin, can lead to toxic levels of the drug. All other foods listed are safe for patients to consume while taking atorvastatin.

Patients who are taking potassium sparing diuretics must be counseled to eat a diet low in potassium. This is due to the fact that consumption of potassium-rich foods, such as orange juice, can lead to dangerously high potassium levels. Excess potassium levels can cause heart arrhythmia and sudden cardiac death.

The kidney is the main route of potassium excretion in the body. During kidney failure, the kidneys are unable to remove excess potassium from the blood. This can lead to hyperkalemia, which can cause nausea, weakness, numbness, arrhythmia, and cardiac arrest.

Vitamin C chelates non-heme iron in food while exposed to the acidic pH of the stomach. This chelated iron then becomes more soluble in the alkaline pH of the duodenum, resulting in increased intestinal absorption of iron.

Vitamin K deficiency can cause a variety of issues related to inability to form blood clots such as petechiae, excessive bleeding, bruising, heavy menses. This vitamin is also an important part of bone and cartilage formation, with deficiency resulting in malformation of developing bones and cartilage, or deposition of calcium into cartilage or arterial walls.