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Kos, a small island in the Aegean Sea, has been known for its silk and wine, as a transportation crossroad, and as a learning center. Perhaps its greatest distinction, however, is its famous resident, “Doctor” Hippocrates.

Hippocrates lived from 460 to 377 BC. I can imagine the wise physician teaching and treating patients at a place of healing called the Asclepion, which was located on a hill overlooking the island. Students from around the world, including his sons, would cling to every word the master physician uttered. Many of modern medicine’s oaths and standards originated from Hippocrates and his students.

This period in history was a time of change. The Greeks were fighting the Peloponnesian war—Sparta versus Athens—and they would eventually fight the Persians and conquer them. This was also a time of deep philosophical thinking. Socrates died in 399 BC after being charged with corrupting the youth by teaching them that there are not many gods. Transportation for war, commerce, and the exchange of ideas enabled knowledge to spread like never before.

Hippocrates and food

Hippocrates had most likely heard of his contemporary, Socrates. He questioned the long-held belief that illness was a punishment from the gods. I wonder whether the traveled physician had access to the Pentateuch (the first five books of the Bible), written by Moses around 1300 BC. Ezra, the scribe, was reading the scrolls in approximately 537 BC, as described by Nehemiah (Nehemiah 8). It’s speculated that by the fourth century BC, parts of the Pentateuch had been translated into the Greek language and would have been available to Hippocrates.

It’s a plausible idea that Hippocrates, a seeker of wisdom, had access to the Bible’s teaching in Genesis 1. In the very first chapter, after creating human beings as male and female, God instructed them about food: “Then God said, ‘I give you every seed-bearing plant on the face of the whole earth and every tree that has fruit with seed in it. They will be yours for food. And to all the beasts of the earth and to all the birds in the sky and all the creatures that move along the ground—everything that has the breath of life in it—I give every green plant for food.’ And it was so” (Genesis 1:29, 30).

Hippocrates could easily have used these truths from Genesis and applied them to his own practice and teachings. The phrase, “Let food be your medicine, and medicine be your food” has been attributed by many to the teachings of Hippocrates. Medicinal uses of plants have been passed down in the history of many cultures, and we now have evidence-based studies demonstrating the truth of this statement.

The National Library of Medicine in Bethesda, Maryland, USA (near Washington, DC), contains thousands of scientific studies related to diet and nutrition that are published every year. Its archive of biomedical publications is called PubMed. This extensive research illustrates the growing recognition that food can treat and prevent disease. Just because something hasn’t been proven doesn’t mean it’s false.

All the inputs into our bodies, physical and mental, are accompanied by physiological changes. How do plants change physiology (the workings of our bodies)? How can plants be used as medication? Hippocrates didn’t have access to PubMed, but we do. By applying nutritional evidence-based studies, physiology can be changed. The foods you choose to eat—your nutrition—can treat as well as prevent disease.

using food as medicine

Modern medicine is great for emergencies and can replace many worn out or genetically imperfect body parts. However, for many of our chronic conditions, plants are an excellent way to begin treatment. These conditions include coronary artery disease, diabetes, hypertension, headaches, gastrointestinal problems, infections, acne, chronic pain, neurological disorders, bone disease, arthritis, inflammation, and obesity. For all of these, plants are an excellent way to begin treatment.

How does one treat these many chronic diseases and slow down genetic aging? A growing number of nutritional experts, including myself, consider plant-based foods, as close as possible to their natural state, to be the ideal treatment. This includes eating a variety of vegetables, fruits, raw nuts, seeds, beans, and grains, together with drinking adequate amounts of water. Also, by avoiding meat, fish, cheese, eggs, dairy, and processed foods, we can reduce many negative effects on our bodies. The internet and many libraries are filled with details on this.

The plant-based goal, in general terms, is that 80 percent of our calories should come from carbohydrates, 10–15 percent from fats, and 10–15 percent from proteins. There may be individual differences because our metabolic genetics are not “black or white.” Plants, in addition to providing calories for energy, have minerals and many other nutrients.

If more than about 15 percent of the calories we consume are composed of fat, our bodies store the extra fat. This storage is a result of the genetically determined chemical processes that occur within us that help us to maintain life. Some people store excess fat in organs such as the liver, others store it in the abdomen, and some store fat in the arteries. However, problems develop when too much fat is stored anywhere in the body. Excess fat leads to negative symptoms and a trip to the doctor.

In short, eating plant food will slow down the aging process. Plants will also give the nutrient composition we were created to have. Will this prevent all disease? No, we all have bad genes and need a Savior.

Plants can be used to treat specific diseases. Medicinal drugs usually change the body’s chemistry for one specific chemical reaction or pathway. This can be termed reductionism. Plants, on the other hand, change our bodies’ chemistry through multiple reactions and pathways. This is termed wholism. Plant chemistry research is now identifying these different reactions and pathways.

the endothelium

Working as I do in the field of cardiology, I am very interested in blood vessels. Blood vessels allow the transportation of oxygen and nutrients to every part of the body while removing toxic wastes. The human body has 60,000 miles of this transport system. The inside lining of our blood vessels is called the endothelium. The endothelium has many functions, including as a barrier that keeps harmful things out and a regulator of elasticity (the ability of the blood vessels to change their shape). It also helps regulate blood clotting. The endothelium also recruits cells for repair, helps grow more vessels when needed, and much more. If we laid all the endothelial cells in our bodies end to end, they would wrap around the world four times! These cells are metabolically active and sensitive to oxidation and inflammation. Oxidation is a chemical reaction that can be thought of as rusting. Inflammation is a condition where the immune cells of the body are activated.

When the endothelium is damaged, important blood flow may be disrupted. If blood flow to the heart is compromised, chest pain or heart attack may occur. A shortage of blood to the eyes can cause blindness, to the brain stroke and memory problems, and to the kidneys, kidney problems. Reduced blood flow to the inner ear can cause hearing loss and dizziness. When blood flow to the legs is insufficient, pain and perhaps limb damage result. Every organ in the body is affected when the endothelium is damaged.

Plants are excellent medicine to help the function of the endothelium. When the endothelial function is improved, all the organs, including the heart and brain, benefit.

Green leafy vegetables contain nitrates. These nitrates trigger the endothelium to release nitric oxide, which dilates the vessels, improving blood flow and the function of the arteries. Arugula, rhubarb, cilantro, and dark leafy vegetables contain nitrates. Beets are another source of nitrate that has been used extensively by athletes to improve athletic performance. I encourage my patients to eat a big salad every day.

Each serving of fruits and vegetables can deliver up to a 6 percent improvement in endothelial function. Blueberries, grapes, acai, and many other plants have polyphenols and anti¬≠oxidants. These antioxidant properties decrease free radicals—unstable molecules that can damage our cells.

Cholesterol that is oxidized is another threat to blood vessels. Oxidized cholesterol increases the risk of heart attack and damage to the endothelium, but fruits and vegetables blunt this threat.

Garlic, turmeric, walnuts, and green tea also improve endothelial function. Many other plants in the future will be shown to help the endothelium. To emphasize again: heart attacks, strokes, and damage to the blood vessels supplying every organ are the result of endothelial damage. Plants can be used to treat the problem, thus helping every part of the body.


It’s estimated that 96 to 97 percent of Americans do not eat the recommended daily amount of fiber. Fiber is the thread, or filament part, of fruits, vegetables, nuts, and grains. The American Heart Association recommends 25 grams of fiber per day for females and 35 grams per day for males. Why is this important?

The intestinal tract has a unique and complex microbiome (the organisms living in the intestines). The 3,000 square feet of enterocytes (the cells lining the gut), are inhabited by trillions of bacteria. There is more genetic material, DNA, in the bowel than anywhere else in the body!

Fiber-eating bacteria in the gut produce short-chain fatty acids, including a substance called butyrate. Butyrate feeds the gut’s good bacteria. When this occurs, the bad bacteria decrease. Fiber helps produce good chemical reactions in the gut. The resulting changes are beneficial on many levels. Inflammation, bad cholesterol, and low-density lipoprotein (LDL) are decreased. Another dangerous chemical, trimethylamine N-oxide, which is associated with heart diseases, is also decreased.

Fiber increases the flow of the foods we eat through the colon. When the flow of materials is faster, less bad chemicals are absorbed into the body, including carcinogens.

Fiber is found in plants. Plants are medications for the gut and can treat many chronic conditions related to gut physiology. Plants improve gut function. Plants help improve endothelial function, which in turn improves health throughout the body.

Science is proving the truths in the Bible. Much can be learned from Genesis 1. Much more will be discovered. The bottom line is this: Dr. Hippocrates was correct: food can be used as medicine.

Dr. James Marcum is a cardiologist with the Chattanooga Heart Institute in Chattanooga, Tennessee, USA. He is also the speaker-director for the Heartwise Ministries radio program. He lives in Ooltewah, Tennessee, USA.

Let Food Be Your Medicine

by James Marcum
From the November 2020 Signs