Which principle is included in the Guidelines for Healthy Americans?

A. While vegans must plan their meals to meet energy needs, getting enough calories is generally achievable with a variety of plant-based foods, including grains, legumes, nuts, seeds, fruits, and vegetables. Caloric intake is usually not the primary nutritional concern.

B. The main nutritional concern in a vegan diet is the potential for deficiencies in nutrients primarily found in animal products. These include calcium (important for bone health), iron (especially the heme form, which is more readily absorbed), zinc (essential for immune function and growth), vitamin B12 (crucial for nerve function and red blood cell formation), and vitamin D (supports calcium absorption and bone health). Vegans can prevent deficiencies through fortified foods, supplements, and careful meal planning to include plant sources of these nutrients.

C. Although a vegan diet can be very healthy when well-planned, it is not without potential nutritional concerns. Without proper planning, deficiencies can occur, particularly in B12 and minerals.

D. While calcium deficiency is a concern, vitamin B6 is generally abundant in plant foods, so it is not a primary concern for vegans. The bigger issues involve B12, iron, zinc, and vitamin D.

A. Vision changes in older adults, such as presbyopia, cataracts, or macular degeneration, are caused by age-related alterations in the eyes themselves, not by saliva production. Vision decline is independent of oral secretions.

B. Smell depends on olfactory receptors in the nasal cavity. Although aging can reduce the sensitivity of smell receptors (hyposmia), this is unrelated to saliva levels, so decreased saliva does not impair olfactory function.

C. Hearing loss, often due to presbycusis or damage to inner ear structures, is not influenced by saliva production. The auditory system, not the oral cavity, governs hearing function.

D. Taste is directly affected by saliva production. Saliva is essential for dissolving food particles so that taste buds on the tongue can detect flavors. In older adults, reduced saliva production, called xerostomia or dry mouth, can diminish perception of sweet, salty, sour, and bitter flavors, make chewing and swallowing more difficult, increase the risk of dental caries and oral infections, and reduce appetite, potentially leading to nutritional deficiencies. Because taste and flavor perception depend on adequate saliva, a decrease can significantly affect food enjoyment and nutritional intake. Managing dry mouth with hydration, sugar-free gum, saliva substitutes, and proper oral hygiene helps maintain taste perception and overall nutrition.