Spinach
Spinach leaves are not only a tasty addition to a salad or stir-fry, they are also nutritious healers.
Spinacia oleracea is an edible annual flowering plant thought to have originated in ancient Persia and then introduced to India and China where it was known as the “Persian vegetable”. The earliest written record was in China around 647 CE and, by the 12th century, spinach was a popular vegetable in the Arab Mediterranean. Its popularity in England and France in the 14th century was due to it appearing in early spring when there were few other vegetables available.
Nutrition
The leaves contain a wide variety of nutrients including chlorophyll and carotenoids (precursors to vitamin A) and important eye nutrients such as lutein and zeaxanthin. Spinach is also an excellent source of vitamins A, C, K and folic acid — a 100g serving contains 20 per cent of the daily allowance of these vitamins. It’s also a good source of manganese, magnesium, calcium, potassium and iron. Vitamin K is important for maintaining bone health and is particularly high in spinach leaves.
It is a source of the B vitamins B2 and B6, vitamin E and dietary fibre. There is some debate about spinach as a source of iron as the oxalic acid levels in it inhibit iron absorption, reducing its bioavailability. Calcium absorption is also affected by oxalic acid — only five per cent of spinach’s calcium content is actually absorbed.
The dark-green colour of spinach indicates a high level of carotenoids and chlorophylls, which have antioxidant and “cleansing” properties.
Healing effects
While spinach is known for its extensive nutrients, it has phytochemicals and bioactive compounds that promote health beyond basic nutrition (including phenolics and nitrates). These compounds have multiple roles in scavenging reactive oxygen species and can modulate the expression and activity of genes involved in metabolism, proliferation and inflammation. They can also curb food intake by inducing the secretion of satiety hormones. All these activities contribute to the anti-cancer, anti-obesity, hypoglycaemic and hypolipidaemic properties of the plant.
Spinach has also shown anti-convulsant activity, it reduces metabolic syndrome and diabetes, lowers abnormal blood cholesterol and assists in the healing of ulcers. Traditionally, spinach was used to alleviate anaemia and for its antibacterial, antiviral and anthelmintic (worm-eradicating) properties.
Eye health
The lutein and zeaxanthin in spinach are important nutrients to prevent macular degeneration and cataracts.
Central nervous system
Spinach is one of the plants highest in the nutrients that improve cognitive function. The phenolic compounds, flavonoids and carotenoids, along with the vitamins and minerals, have produced an increase in acetylcholine in the hippocampus (area of the brain responsible for memory and learning), along with a neurogenic growth factor that is critical for the repair and restoration of the neural circuitry in the brain.
In a study on healthy men and women, a diet including extra spinach and a combination of spinach and apples showed that consuming these high-flavonoid and high-nitrate foods reduced the risk for both cardiovascular disease and cognitive decline.
Cardiovascular system
The flavonoid compounds in spinach enhance nitric oxide levels, which lowers high blood pressure and improves heart muscle function. This pathway improves arterial stiffness, reduces inflammation and improves platelet function and exercise performance. A diet high in spinach has implications for improving cardiovascular health.
Insulin resistance and diabetes
The nitrates in spinach have other positive benefits: improving nitric oxide status will enhance lipid metabolism, relieve inflammation and prevent the development of insulin resistance.
Cancer inhibition
Research has shown that the glycolipid fraction of spinach is a promising suppressor of solid tumours, making spinach a healthy food with anti-tumour activity.
Detoxifying and deodorising
Chlorophyll (with magnesium as the central core of its molecule) detoxifies the body and will clean the breath after consumption of foods such as garlic. It has major antioxidant properties.
Eating your spinach
To obtain optimal nutrients, spinach leaves need to be steamed and eaten with a little oil: olive oil, macadamia oil, coconut oil, ghee or even a little organic grass-fed butter. This applies particularly to absorbing the nutrients lutein, beta-carotene and zeaxanthin.
Safety
Like most leafy green vegetables, spinach contains a high amount of oxalate (oxalic acid). Individuals with a history of oxalate-containing kidney stones should avoid overconsumption. Oxalic acid may also inhibit the absorption of other minerals but it has a positive relationship with the nitrate content of the vegetable. Lightly cooking spinach is thought to reduce its oxalic acid content without adversely affecting the nitrate content.
