Eating a Rainbow of Plant Foods

Another chapter in our Food as Medicine blog...

Phytochemicals are responsible for many of the sensory qualities of foods and beverages as well as providing a diverse range of health benefits. Plant foods contribute thousands of phytochemicals to the human diet. Each plant food contains a diverse range of phytochemicals. For example, an orange contains over 170 different phytochemicals including 60 different flavonoids (Consumer Science Program CSIRO Health Science & Nutrition, 2003).

Phytochemicals are not classed as nutrients but, nevertheless, seem to contribute significantly to protection against degenerative diseases. Antioxidants are molecules that stabilise free radicals. Excessive free radicals can damage DNA and other genetic material.

The main classes of phytochemicals that are of interest in the study of food and beverages are as follows:

Carotenoids - these are responsible for the yellow, orange and red colours of many plants.
Chlorophyll - this is the pigment that gives plants and algae their green colour.
Phenolics (Polyphenols) - a subgroup is flavonoids and important flavonoids include anthocyanidins, hesperidin, isoflavones and quercetin. Flavonoids and anthocyanin are powerful free radical scavengers.
Organ Sulphur Compounds - found in cruciferous vegetables such as cabbage.
Nitrogen-Containing Compounds - many plants contain compounds that are the same as those produced by humans such as hormones and neurotransmitters. Cherries contain the hormone melatonin.

A practical way to ensure your diet contains a variety of health promoting phytochemicals is to include plant foods of all colours in your meals. You will also get the fibre, vitamins and minerals your cells need. Let's find out which foods are good sources of different coloured phytonutrients (Garner J., 2019)

RED - (Lycopene)

Ruby grapefruits, red grapes, strawberries, cherries, watermelons, tomatoes, red peppers, beetroots

YELLOW/ORANGE - (Beta-carotene)

Apricots, rockmelons, mangoes, peaches, carrots, sweet potatoes, yellow & winter squashes, pumpkins, yellow & orange peppers

GREEN (Chlorophyll)

Leafy greens like lettuces, kale, spinach, broccoli, brussels sprouts, cucumber, zucchini, avocados

BLUE/PURPLE (Anthocyanins)

Blackberries, black currants, blueberries, grapes, raisins, plums, red cabbages, eggplant

WHITE & TAN/BROWN (Allicin & Quercetin)

Garlic, leeks, onions, shallots, cauliflower, white potatoes, bananas, brown pears (Garner J., 2019)

It is important to incorporate a variety of foods from each of these 5 -colours into your diet regularly. You don't have to eat them all every day, but very often is a good idea. And it's very easy to do! Just cover half you plate at every meal with vegetables and fruit. (Garner J., 2019)