In ancient Greece, physician-philosophers were struck by how many plants looked like a body part. They wondered if nature was trying to tell them something. From this observation, they developed the ‘doctrine of signatures’—a claim that certain plants could heal the organ that they resembled of an illness. It may seem like nonsense, however, says nutritionist Jane Hutchens of Lemongrove Road Holistic Health in Penrith, it’s not so far-fetched.
Two thousand years ago there was no division between the sciences as we understand them today and other areas of enquiry such as medicine, philosophy and astrology. Early physicians like Dioscorides (40–90AD) and Galen (129–200AD) knew that plants had medicinal and health properties. They understood that prescribing the right plant for the right ailment was a task made easier by the appearance of the plant—the ‘signature’ (distinctive mark) of the illness or organ could be matched to the ‘signature’ of the plant. “For example,” says Jane, “plants with yellow flowers, like gentian and dandelion, would be used to treat conditions that caused jaundice (yellowing of the skin).”
The 16th century Swiss-German physician Paracelsus (the founder of toxicology—as well as an alchemist and astrologer) said, “Nature marks each growth… according to its curative benefit.” A century later English botanist William Coles declared that this was evidence of God’s work—by making plants look like the body parts they were able to heal. He (God) was helping humans to help themselves.
Perhaps the most uncanny resemblance of a plant to a person is Korean ginseng. “Korean ginseng root can grow to look just like a human body,” says Jane, “and the ones that do are the most prized.” Perhaps not surprisingly, Korean ginseng has been used to treat ailments almost anywhere in the body, particularly in traditional medicines.
The doctrine of signatures was used right up until the ‘rational men of science’ of the 19th century dismissed all such old knowledge as ‘old wives’ tales’, but a resurgence of scientific interest in natural remedies, and the pharmaceutical properties of plants, has shed new light on the doctrine of signatures.
“Interestingly, we now have scientific knowledge of the constituents of plants that support their use in these conditions,” says Jane. “The doctrine of signatures has been used in many contexts, and is interpreted by the shape, colour and place of growth of a plant. While I wouldn’t base my diet on it—it is too hard to find foods for every organ—here are some ‘signatures’ that match our bodies with our dinner plates.”
Matching our bodies to food
Crack open the hard shell of a walnut and inside you have a brain-shaped nut, with folds and wrinkles just like the cortex—and even left and right hemispheres. No prizes for guessing what these are good for! “Walnuts are one of the best sources of omega 3 fatty acids,” says Jane, “and omega 3 is concentrated in the brain. They are strongly anti-inflammatory and are important for memory, mental function, behaviour and reducing the risk of depression and dementia. Researchers also believe that walnuts help to make several neuron transmitters, which transport the messages from nerve to nerve in the brain.”
Everyone has heard the old wives’ tale that carrots help you see in the dark. Slice a carrot and you will see that it has a central core and radiating lines—like an iris and pupil. The origin of this claim is more recent than the ancient Greeks. In World War II the British mounted a propaganda campaign that attributed their ability to spot German bombers to their carrot-loving pilots. The truth was top-secret—the British had developed Aircraft Interception Radar and didn’t want the Germans to know about the new technology. So, is there any truth in this one?
“Carrots have loads of beta-carotene, and other nutrients, that improve blood flow to the eye and can reduce the risk of developing cataracts and age-related macular degeneration,” says Jane. They are also full of Vitamin A, which—if you are suffering from Vitamin A deficiency-related night-blindness—can improve your night vision.
Turn an avocado upside-down and it has a similar shape to the womb. “The avocado has plenty of benefits for a woman’s uterus and reproductive system,” says Jane. “The healthy fats help reduce inflammation and pain, and also contribute to making hormones. The avocado also has good amounts of folate, which is essential in making blood cells and DNA, and is important not only for preventing neural tube defects in babies, but also for reducing the risk of cervical dysplasia (pre-cancerous changes in the cervix).”
Dem bones, dem celery bones
Take a look at a stick of celery and observe how it is long and has a central hollow. “Not all bones are long and lean,” says Jane, “but the long bones in your arms and legs are. Both have long channels that provide support and strength, as well as channels for nutrition. Celery contains Vitamin K which is essential in binding calcium and building strong bones.”
Citrus is breast
Citrus fruit has two signatures that correspond to health, and particularly breast health. Did you know that—like citrus—breasts are divided into segments, with fibrous connections maintaining the structure and shape? Or that women with low levels of Vitamin D are more at risk from breast cancer? “Citrus is a bright sunny fruit, and sunshine is the best source of Vitamin D,” says Jane. “Citrus also has a compound called liminoid which can reduce the risk of cancer. The pith (the spongy white tissue lining the rind of oranges, lemons, and other citrus fruits) is full of flavinoids which help tissue strength and enhance lymph fluid circulation—and Vitamin C is an antioxidant good for tissue health.”
Beetroots might be more purple than red, but they are heart-shaped and grow with long, artery-like rootlets. “Beetroot has betaine and folate which lower homocysteine—an amino acid that increases the formation of clots and atherosclerosis. Beetroot also contain nitric oxide which lowers blood pressure, and potassium which normalises heart rhythm, rate and blood pressure.”
It takes a few steps to connect the ‘signature-named’ kidney bean to its organ, however the link can be made. “Kidney beans (and other legumes) are low-GI high-fibre foods, which means they help stabilise blood sugar levels, which can reduce the risk of developing diabetes. Kidney beans also help reduce blood pressure. Up to 30% of people with diabetes will have some kidney damage, and hypertension is a major risk factor for kidney disease too. So kidney beans help reduce the two main risk factors for kidney disease.”
Clams bear a passing resemblance to testicles, and contain folate, zinc and selenium for sperm health.
I love tomatoes
Red and with chambers like a heart, tomatoes are rich in lycopene which reduces the risk of heart disease.
Red wine is rich in antioxidants and phytonutrients (from grapes) called polyphenos, which reduce unhealthy cholesterol (LDL) and in turn reduce the risk of heart disease and stroke.
A grape big breath
The alveoli and bronchioles in your lungs look a lot like bunches of grapes, and grapes are great for lung health. They contain proanthocyanidin, which is anti-inflammatory, and helps the alveoli stretch as you breathe. A diet rich in proanthocyanidins is associated with a reduction in lung diseases such as emphysema, asthma, bronchitis and cancer.
Almonds are rich in Vitamin E, which slows macular (of the eye) degeneration.