Tender stalks of asparagus peeking their heads through the soil and emerging after a long winter is a welcome sign of spring for those who grow it. Others, like me, like to see the pickup trucks on the side of the road offering fresh asparagus for sale. Eaten raw as part of a vegetable platter, or grilled with lemon juice and olive oil, asparagus is a delicious snack or addition to a meal. But this vegetable brings more than nice flavor to the table; it’s no slouch when it comes to health benefits.
Like other green vegetables, asparagus is a good source of several nutrients, particularly folate and vitamin K1. It also contains significant amounts of iron, copper and manganese, along with vitamin C and carotenes. As a non-starchy vegetable, it’s low in carbohydrate and high in fiber, making it a good go-to for low-carb dieters and vegetarians alike.
Aside from its impressive nutrient profile, asparagus contains compounds that have demonstrated anti-cancer effects on human colon cancer cells in vitro. Asparanin A, a steroidal saponin extracted from asparagus, has been shown to induce cell cycle arrest and apoptosis in human hepatocellular carcinoma cells. Polysaccharide compounds extracted from asparagus have also demonstrated impressive anti-cancer effects on liver cancer by regulating expression of genes involved in apoptosis. The authors of one study suggest these compounds could be used as a “chemosensitizer,” making cancer cells more susceptible to the cytotoxic effects of mitomycin and other drugs. I like to suggest that some cancer patients puree asparagus and consume at least 2-4 tablespoons per day.
Asparagus compounds have shown potential benefit in other health concerns beyond cancer. Extracts of asparagus have attenuated signs of cognitive impairment in mouse models of Alzheimer’s disease. Interestingly, in contrast to the effect of these compounds on cancer cells, when applied to neuronal cells from models of dementia, the asparagus extracts have anti-apoptotic and cytoprotective effects. In cells treated with the asparagus compounds, the release of lactate dehydrogenase—used as a marker for neuronal cell damage—was significantly reduced upon exposure of the cells to hypoxia mimicking agents.
Asparagus also has beneficial effects on kidney health. In a rat model of hypertension, compared to a diet with no asparagus, an experimental diet that contained 5% asparagus led to significant reductions in systolic blood pressure, and creatinine clearance was higher in the treated group. The reduction in blood pressure is believed to be due to 2’-hydroxynicotianamine, a compound isolated from asparagus, which exhibits angiotensin-converting enzyme (ACE) inhibiting activity.
Another health concern upon which asparagus might prove beneficial is chronic stress. In a mouse model of stress induced by sleep deprivation, an asparagus extract was shown to reduce levels of corticosterone and lipid peroxide, two markers for stress. Compared to untreated controls, mice treated with the asparagus extract had elevated levels of heat shock proteins, the induction of which is believed to be cytoprotective.
If you’ve only ever seen the common green asparagus, you might be surprised to learn there are purple and white varieties, too. Purple asparagus owes its color to higher amounts of anthocyanins, phytochemicals that also lend color to blueberries, raspberries, and other similarly colored fruits and vegetables. The purple variety tends to be sweeter and have thicker stalks than the green. White asparagus retains its white color because the stalks are grown under a mound of soil, preventing the development of chlorophyll and the emergence of the green pigment.