Eat a Rainbow - But Why?
Many people recommend eating all the colours of the rainbow and I believe this is good advice. Different colours contain different types of phytonutrients that help reduce the risk of chronic diseases such as diabetes, heart disease, and cancer, and they also help our immune system function optimally and help our detoxification pathways. Phytonutrients are compounds that are found in fruit and vegetables, nuts, seeds, herbs, and spices. Phytonutrients come in many colours as the advice of “eat a rainbow” suggests, green, yellow/orange, blue/purple/black, red, and white/tan/brown.
Generally darker coloured plants have the highest phytonutrients but all colours contribute to good health. This is why it is important to try and get as many different colours into your diet as possible.
The colour red is thought to help the brain, liver, heart, immune system, and protect against certain cancers. Foods such as cranberries, cherries, strawberries, goji berries, raspberries, pomegranate, red bell peppers, red onions, and rhubarb are all good choices to make when choosing foods from the red coloured family. There are many beneficial compounds found in these foods such as ellagic acid which is found in pomegranate and helps your liver get rid of toxins from the body. Lycopene may protect against prostate, breast, and skin cancer, and reduces the risk of heart attack.
When it comes to the orange coloured foods two main compounds tend to come to mind one being beta-carotene and the other bioflavonoids. Beta-carotene can convert to vitamin A in the body and vitamin A has been associated with healthy vision, supporting the immune system, and healthy bones to name a few. Beta-carotene is actually just one member of a group of beneficial compounds known carotenoids. When eating carotenoids it is a good idea to have some kind of fat with them to help shuttle them into the body, so drizzling some olive oil over them can be a good idea. Bioflavonoids work synergistically with vitamin C and help keep the immune system strong, reduce the risk of heart attacks, help with vision, and maintain strong bones. Oranges, peaches, and grapefruit all contain bioflavonoids.
Yellow coloured foods contain anti-inflammatory compounds, and may protect the skin, eyes, brain, and vascular system. The list of foods is a lot smaller when it comes to the colour yellow with bananas, pineapples, summer squash, and lemon being some good choices. I don’t like to eat fruits with a thick skin personally and tend to choose fruits with a lower glycemic index when I do eat them so out of this group I mostly use lemon. Adding it to water can help alkalize the body and it also contains bioflavonoids.
The biggest group of coloured foods is the green colour. They have many beneficial qualities such as protecting the brain, heart, liver, and skin, they are anti-cancer and anti-inflammatory, and can also support the balance of the hormonal system due to the indoles and phytoestrogens found in these foods. The cruciferous vegetables like broccoli and Brussel sprouts contain a compound called glucosinolates and this is why they are thought to be excellent anti-cancer foods. These glucosinolates, when chopped or chewed, turn into active compounds like indole-3-carbinol and sulforaphane. These help support the way estrogen is broken down in the body and is why they are related to a decreased risk in estrogen related cancers such as breast and uterine cancers. Many people supplement with these compounds now so you may be familiar with them. Green coloured foods also contain plants sterols that can block the absorption of cholesterol in the gut and can reduce LDL cholesterol. A small list of foods from this list would include broccoli, celery, Bok choy, cabbage, and avocado.
The blue/purple/black coloured foods are some of my favourite as they are related to brain health. I like anything that can support brain function and these foods can help memory, cognition, and protect the brain from damage. Berries such as blueberries, blackberries, and boysenberries are some of the options you have with this colour. The thinner the skin of a fruit, the higher its antioxidant content tends to be because they have to protect themselves from the sun. The most popular compound found in the blue/purple category would be resveratrol. Resveratrol has been associated with longevity, reducing inflammation, supporting heart health, and reducing blood sugar. It is the compound in wine that most people refer to when they talk about the health benefits associated with drinking red wine. Some other food choices you have are cabbage, eggplant, grapes, and figs.
White/tan/brown foods include nuts, seeds, vegetables, fruits, and spices, not processed foods such as cereals, breads, pasta, cakes, and cookies. We are talking about whole foods in their natural state. Like the green foods they contain compounds that help liver health, hormone balance and they also have anti-inflammatory and anti-cancer benefits. Cauliflower, garlic, mushrooms, onion, coconut, pears, and nuts (cashews, Brazil, almond, walnut) are all good food choices in this category. Garlic and onion contain sulfur compounds which help protect against cardiovascular disease, cancer, and inflammatory diseases, while mushrooms can enhance the immune system.
A simple way to get more colours into your diet is to make sure you have all types of colours in your basket the next time you go shopping. Trying a new food each week will also help as it will get you out of your normal routine and most likely introduce a new colour. Making a stir-fry or soups can also help with variety.
The old advice of 5 servings of fruit and vegetables each day is too low and you should really be aiming for 9 servings a day as a minimum. I am not a huge fan of fruits as I tend to gain body fat from eating them so I choose the lower glycemic choices such as berries and get the rest of my servings from vegetables like leafy greens and vegetables from the cruciferous family.
Another good tip is to use many herbs and spices on your food. I used to be a very boring eater and just eat the food without any seasoning at all. Adding herbs and spices to your food increases the phytonutrient content but also increases the taste. Just check the label to ensure you aren’t buying
fillers along with your herbs and spices. Some tend to contain sugar, gluten, artificial colours, and preservatives.
Hopefully this has given you some information on why you should try and eat all the colours of the rainbow and maybe knowing some of the benefits, you may be keen to give it a go.