We all get the relationship between healthy foods, including vegetables, and our quality of life. Weight, energy, illness and mood are all known to be affected by what we eat and drink.
Is there also evidence that vegetables can emulate medicine? Will eating certain vegetables result in the same outcome as taking a pill? Can foods actually stop, reduce or reverse medical conditions?
Discovering recent research that suggests broccoli can reduce the impact of Covid 19 SARS-CoV-2 quickly engaged my interest in plants as medicine.
A study led by Dr. Alvaro Ordonez, Division of Infectious Diseases, John Hopkins University School of Medicine, published this March, indicates that, “Sulforaphane exhibits antiviral activity against pandemic SARS-CoV-2 and seasonal HCoV-OC43 coronaviruses (a variety of common colds) in vitro and in mice.”
Sulforaphane (SFN) is a biologically active, sulfur-rich phytochemical found in vegetables like broccoli, kale, cauliflower, bok choy and cabbage, a group known as cruciferous vegetables.
The study was specific in indicating that sulforaphane impeded in vitro replication of six strains of SARS-CoV-2 including Delta and Omicron variants. Further, they discovered that SFN acted in synergy with Remdesivir, an antiviral medication now approved in Ontario to fight Covid in those presenting symptoms. When the two compounds were combined the effectiveness of each was increased.
Although studies based on human trials have not been completed, Ordonez published results of SFN treatments on laboratory mice. His team concluded that administering SFN to mice prior to infecting them with SARS-CoV-2 significantly decreased the virus’ reproduction in the lungs and upper respiratory tract compared to untreated mice. The result was reduced pulmonary pathology and lung injury in those treated with SFN.
He concluded the study’s abstract by stating, “SFN should be explored as a potential agent for the prevention or treatment of coronavirus infections.”
He failed to note that this result would unleash millions of texts, emails and phone calls from mothers worldwide reminding their kids, “See, I told you to eat your broccoli!”
Are there other vegetables that have similar medicinal properties?
The number of such verifiable claims is surprisingly large. Since we live in the prolific vegetable garden known as southern Ontario, what can we learn before summer harvest arrives?
Let’s include a caution here that all research and studies are not equal, and sometimes studies are designed to prove a hypothesis rather than provide unbiased evidence. This column is not meant to endorse naturopathic medicine over traditional, nor to suggest replacing medications with vegetables. Balanced, healthy diets can help lower the risk of diabetes, heart disease and some cancers, and quality foods are the best means of providing the energy our body needs to fight disease, but no individual food or diet can necessarily cure these illnesses. Nor can food provide the fast results many medicines offer.
Broccoli also illustrates that the medicinal or health-improving value of vegetables, and foods in general, can be significantly affected by how they are prepared.
Sulforaphane exists in cruciferous vegetables as glucoraphanin, an inactive plant compound. When the vegetable is damaged it releases myrosinase, an enzyme responsible for the plant’s defense, which causes the glucoraphanin to activate sulforaphane. This family of vegetables will not release its beneficial SFN until it is chopped, cut, blended in a smoothie or chewed.
Raw cruciferous vegetables have up to ten times more SFN than when boiled or microwaved because temperatures above 140 C destroy their available glucosinolates. To maximize the anti-viral capabilities of broccoli, cauliflower or cabbage, eat it raw or lightly steamed.
Cruciferous vegetables have additional medicinal values. The U. S. National Institute of Health says, “Sulforaphane has been shown to have anti-cancer properties in a number of test-tube and animal studies, reducing both the size and number of various cancer cells.” Although studies don’t yet quantify the specific effectiveness of various quantities of SFN we might ingest from vegetables, there is abundant research to conclude that a high dietary intake of cruciferous vegetables is linked to a significantly reduced risk of cancer.
Tomatoes, although technically a fruit, are another example of a natural disease fighter. They contain lycopene, an anti-oxidant powerful enough to qualify as medicinal. Best known for its prostate cancer fighting ability, additional research shows that lycopene can inhibit the growth of numerous other cancers such as colon, lung, stomach, breast and cervical by protecting our immune system.
Tomatoes also contain lutein and zeaxanthin, anti-oxident carotenoids found in the lens of our eyes as macular pigments which filter out blue light rays that can damage eye tissue. Studies confirm these compounds help protect us from age-related macular degeneration, a disease of the retina, and the primary cause of blindness in North America. In a world full of blue light emitting computer screens, tablets and phones, tomatoes are truly preventative medicine.
These benefits are affected by whether tomatoes are cooked or eaten raw. Lycopene is more readily absorbed by our bodies when tomatoes are cooked, but heating reduces the amount of other valuable nutrients available.
Crushed or chopped garlic produces allicin, an antiviral and antibacterial. Onions release quercetin when eaten, also a strong antiviral. Adding garlic and onion to cooked tomatoes in a spicy pasta sauce, with a raw tomato cucumber salad on the side, makes a meal that qualifies as delicious natural medicine.
Beets are packed with nitrates, folate and anti-oxidant alpha-lipoic acid. Half a litre of beet juice per day significantly reduces blood pressure in healthy people. Folate is essential to creating our DNA, therefore requisite during early pregnancy to reduce the risk of spine and brain birth defects. Alpha-lipoic acid also combats diabetes-related nerve damage.
These benefits accrue whether beets are cooked or eaten raw.
Carrots are considered nutritionally packed enough to have medicinal value. They contain lutein and zeaxanthin, both important for vision as mentioned above. Equally important, a 2018 meta-analysis (a study of studies) of ten major studies published by the U.S. National Library of Medicine designed to define the relationship between dietary carrot intake and the risk of breast cancer concluded, “That high carrot intake was associated with decreased risk of breast cancer.”
Bright-coloured bell peppers, like carrots, are rich in carotenoids, and also phenols and flavonoids. Animal studies show that these compounds are effective in preventing memory loss in those with Alzheimer’s. Consuming colourful bell peppers appears to inhibit the beta-secretase 1 enzyme present in our brains from releasing the amyloid proteins which latch onto nerve fibres, increasing the risk of brain malfunction and Alzheimer’s.
Sweet potatoes provide another example of why it is important to know how vegetable preparation impacts medicinal value. Boiled sweet potatoes have a low glycemic index, which means they help control blood sugar by slowing glucose release into our bloodstream. They also reduce LDL (bad) cholesterol, which protects our heart. However, because they are high in carbohydrates, baking, roasting and frying sweet potatoes dramatically raises their glycemic index, causing blood sugar levels to spike.
Food selections and diet choices have been utilized to treat and prevent illness for centuries. Science and research have improved rapidly, dramatically increasing our understanding food and its benefits and dangers. Unfortunately for many societies, this parallels a decrease in the quality and diversity of food we consume.
Information on vegetables as medicine is easily accessed. Reasonable diligence will separate fact from promotional content. There is no downside to becoming informed and food-curious prior to making our dietary decisions. ◆