by Tammera Karr, PhD
One late night, I traveled back in time with “Food Fights – Culture and War” by Tom Nealon. It is always exciting to read some little tidbit of history that gives you an ahhaa moment. That is the case with lemons and citrus, utilized heavily in Mediterranean diets.
I came upon an interesting section on Lemonade and the plague; it turns out lemonade became a trendy drink in the 1640’s in Italy and Paris. When the second round of plague hit in the 1660’s cities like Venus, Naples, and Paris were relatively untouched unlike the first round were 100,000 people died. Author Tom Nealon tracked down the role of lemonade a popular and trendy beverage of the time. Lemonade was sold from street stalls and made in homes, the peal and citrus off cast went into the street/alley and dock trash piles frequented by rats which carry the flea that hosts the bacteria responsible for the plague. The rats fed on the citrus filled with limonene (Limonene is a clear, colorless liquid hydrocarbon classified as a cyclic monoterpene, and is the major component in oil of citrus fruit peels) which it turns out kills the bacterium responsible for the plague….so the population was saved due to the rats and people being healthier from eating and drinking lemons. NOW I know why the Italians have such a big citrus drink culture.
Citrus are native to southeastern Asia but have been grown in the Mediterranean basin for centuries. The citrus trees and fruit are of great importance in Mediterranean countries and, in the case of orange, mandarin, and lemon trees, they found the Mediterranean area soil and climatic conditions perfect to develop high fruit quality. 
Of all citrus fruits, lemons and limes have the highest citric acid content, about 1.4 grams per ounce, or about 8 percent of their dry weight. Lemons and limes also contain ascorbic acid, or vitamin C, and malic acid. Citric acid from lemons and limes is often used as an additive in food preparation, both to add a tart flavor and as a preservative. For example, citric acid helps prevent browning of fresh vegetables and maintains the color of meat during storage. It also prevents the crystallization of sucrose in candy and promotes flexibility and separation of cheese slices.
Lemons also contain a small amount of malic acid, which is tart but enhances the sweetness of sucrose in fruit, according to an article published in the Journal of Experimental Botany in March 2006. The human body also produces malic acid. According to NYU Langone Medical Center, malic acid may have therapeutic benefits for individuals with fibromyalgia. People with fibromyalgia may have trouble using or producing malic acid, which can affect normal muscle function. 
Epidemiological studies have shown an inverse relationship between dietary flavonoid intakes and cardiovascular diseases. Citrus fruits are the main winter fruits consumed in the Mediterranean diet, so they are the main source of dietary flavonoids. The possible beneficial effects are due, not only to the high amounts of vitamins and minerals but also to the antioxidant properties of their flavonoids. Dietary flavonoids may help to supplement the body antioxidant defenses against free radicals. These compounds’ beneficial effects are due to their antioxidant activity, which is related to the development of atherosclerosis, cancer, and to anti-inflammatory and antimicrobial activity. , 
 ciTrUS aS a comPonenT of The meDiTerranean DieT: https://www.researchgate.net/publication/311911612_Citrus_as_a_Component_of_the_Mediterranean_Diet