The adage “feed a cold, starve a fever” got its start in Hippocrates day and proved the popular prescription up to the 19th century. Yet, given our modern medical wisdom, does this lore hold up today as the right way to treat common upper respiratory tract infection (URTI) symptoms like cough, runny nose, sore throat, headache and fever? No. Instead, the 21st century rendition should read: “Feed a cold, feed a fever.”
The root of this old saying came from the observation that not eating — or in other words, a state of starvation — lowered body temperature, and thus, seemed to cure a fever. In the late 19th century, physicians flip-flopped when they found that for every degree Celsius a fever elevated temperature, a person’s metabolic rate (the rate at which the body burns calories) increased 10 percent. Hence, treatments turned towards “feeding a fever” to prevent weakness and weight loss.
Nowadays, we know that starvation can promote the body’s immune system to fight against bacteria, but not viruses. What’s more, fasting and dehydration can reduce the body’s antiviral immune response. These are both facts important to note since most upper respiratory tract infections are caused by viruses.
When treating an upper respiratory tract infection, drink! Keep hydrated with water, juice, broth and soups. Eat a balance of protein, carbohydrates and fats, plus a wide variety of vitamins, minerals and phytochemicals, or plant-based nutrients.
Also consider the preventative power of probiotics. Research published in 2018 in the journal Synthetic and Systems Biotechnology looked at adults who had experienced an URTI four or more times during the past year. When given a 6-ounce serving of a yogurt drink containing three probiotic organisms once a day for 12 weeks, these folks experienced an immune system boost, as tested by blood levels of interferon, interleukins and immunoglobulins — and this boost helped to prevent flu-like respiratory infections. The specific probiotics used were Lactobacillus paracasei, Lactobacillus casei and Lactobacillus fermentum — all found in some commercial yogurts, certain cheeses like aged cheddar and Parmigiano Reggiano, naturally fermented vegetables and Sicilian green olives.
The bottom line is, if you have fever due to a cold or flu, keep well hydrated — and eat!
Carol Bareuther is a registered dietitian and freelance health and nutrition writer.