Scurvy is a disease caused by a deficiency in Vitamin C. Early symptoms can include weakness, feeling tired, and sore arms and legs. Without treatment, gum disease, decreased red blood cells and bleeding from the skin can occur.
“Although they didn’t know it at the time, it was the earliest seafaring explorers who were responsible for discovering vitamins.
On their long voyages, sailors would almost exclusively eat dehydrated foods and fish with little or no fresh fruit or vegetables.
Sailors would start to show symptoms of scurvy such as weakness, tooth loss, and bruising after 10 to 12 weeks on their voyage. Once those sailors got to land and started consuming “acid fruits”, their symptoms would disappear in one to two weeks.
The British navy observed this and adopted the use of citrus juice from lemon or limes into the sailors’ daily rations, curing the disease for their sailors.” – Dr. Brian Dixon
Eating processed foods can also contribute to feeling tired (sometimes known as a Sugar Crash) and weakness due to muscles not having the needed nutrients for development and recuperation.