A fever is a temporary elevation in the body’s temperature, signaling the immune system is actively responding to an illness. When fighting an infection, eating and drinking can become complicated, leading people to question which foods are safe or beneficial. Dairy products, a common source of nutrition, often spark debate about consumption during sickness. This article provides guidance on consuming dairy while experiencing a fever, focusing on scientific evidence.
Addressing the Mucus Myth
A persistent belief is that consuming dairy products, particularly milk, increases the production of respiratory mucus or phlegm, potentially worsening congestion. This notion is not supported by scientific evidence. Studies involving volunteers exposed to a common cold virus showed no statistically significant association between milk consumption and an increase in nasal secretion weight or other respiratory symptoms.
The impression that dairy creates more mucus is considered largely perceptual, not physiological. When milk mixes with saliva, it creates a slightly thicker texture in the mouth and throat, which mimics the sensation of having thicker mucus or a coated throat. This temporary feeling does not translate into an actual increase in the body’s mucus production.
Individuals who already believe the “milk-mucus” myth often report more symptoms of congestion when consuming dairy, even though objective measurements show they do not produce higher levels of nasal secretions. For the majority of people, avoiding dairy during a fever solely to decrease phlegm is unnecessary. Dairy remains a source of protein, calories, and fluids, which are beneficial when appetite is low.
Dairy and Digestive Sensitivity During Illness
While the mucus concern is unfounded, dairy consumption during a fever can sometimes lead to digestive discomfort. Systemic illnesses, especially those involving the gastrointestinal tract, can temporarily disrupt normal digestive processes. High fever and general sickness can also stress the small intestine, which produces the lactase enzyme.
Lactase is the enzyme required to break down lactose, the sugar found in milk, into simpler, absorbable sugars. Illness can cause a temporary reduction in lactase production, leading to secondary lactose intolerance. If lactose is not digested in the small intestine, it moves undigested into the colon.
Bacteria in the colon then ferment the undigested lactose, a process that releases gas and organic acids. This fermentation causes uncomfortable symptoms such as abdominal cramping, bloating, excess gas, and diarrhea. This temporary digestive sensitivity is the main reason a person might experience gastrointestinal distress after consuming dairy products while sick.
Practical Choices: Best and Worst Dairy Options
When consuming dairy during a fever, focus on products that are low in lactose and easier to digest. Cultured dairy products, such as yogurt containing live and active cultures, are often well-tolerated. The beneficial bacteria in these products help pre-digest much of the lactose, making it easier for the compromised digestive system to handle. Kefir, a fermented milk drink, also has a lower lactose content and provides hydration and nutrients during illness.
Hard, aged cheeses like cheddar, Parmesan, and Swiss are excellent choices because they naturally contain very little to no lactose. The lactose is removed or converted during the cheesemaking and aging process. Plain, low-fat milk can also be acceptable, especially if consumed in small amounts with other foods, as it aids in hydration and provides calories.
Products high in lactose or high in fat should be approached with caution. Whole milk and ice cream have both a higher lactose and fat content. High-fat foods slow down the stomach-emptying process, which may cause heaviness or nausea when the body is under stress. Full-fat dairy may contribute to overall digestive discomfort more than low-fat or cultured options.