How healthful is my vegetable garden?
Phytonutrients are naturally occurring chemicals produced in a variety of plants. They have been associated with increased health benefits, acting as chemopreventive agents against many forms of cancer and some chronic diseases. Many vegetables produce phytonutrients. This often occurs in response to some level of perceived stress, either environmental (heat, drought, light) or pest pressure (insects, disease). However, the amount of phytonutrient production can also vary significantly across varieties of a specific vegetable.
Phytonutrients and their connection to health
The ability for plants to produce these unique compounds has evolved to help them survive in the environment where they grow. In essence, this ability has become the plant's own defense arsenal. It has recently been discovered that these same compounds have been associated with the prevention of cancer and other chronic diseases. While many more studies need to be conducted to demonstrate their clear effectiveness in humans, evidence continues to mount in the scientific community illustrating their cancer prevention potential.
Something as simple as choosing the right vegetable variety for your garden may bring greater health benefits to your table.
These phytonutrients may act in a number of ways to prevent cancer: through helping to repair DNA damage, by enhancing the detoxification of carcinogens we are exposed to, and by boosting the process of cancer cell self-destruction in the event cancer cells occur.
Since the potential benefits of these phytonutrients are affected by temperature, excessive cooking is not recommended (brief stir-frying or steaming are better alternatives). Fresh consumption is preferred for maximum benefit. The chart below (Figure 1) represents the collective, relative concentrations of key phytonutrients known to have cancer prevention potential. The different colored leaves represent the relative concentration of the individual phytonutrients: glucoraphanin (dark green), glucobrassicin (medium green), and gluconasturtiin (light green). Studies are continuing that will add more varieties to the list.
Not all phytonutrients work for everyone. Effectiveness depends upon a person's genetic makeup (nutrigenomics). Science suggests “benefits are possible,” that “there are strong indications of efficacy” or that “positive effects may result” from eating chemopreventive foods. While epidemiological evidence of effectiveness is based on studying populations, diets and disease, scientists continue to work to verify and quantify the specific potential benefits. So there may be even more reasons why it is good to eat your vegetables!
Figure 1. Which vegetable and variety may be healthier? Three year summary of relative phytonutrient concentrations of select vegetable crops. Research conducted at the University of Minnesota.
Figure 2. Which vegetable and variety grew best? Three year summary of yield and relative maturity of select vegetable crops. Research conducted at the University of Minnesota.