Why eating the rainbow isn’t always healthy

Good example: white foods get unfairly dismissed as "nutritionally empty" because they lack colour, but plenty of white foods are packed with nutrients, cauliflower, garlic, onions, white beans, mushrooms, potatoes (skin-on), and parsnips all bring fibre, vitamin C, potassium, or antioxidant compounds that don't happen to be pigmented.

Flip side: red velvet cake is red, but the colour comes from food dye, not from any nutrient, no antioxidants, no fibre, none of the compounds that make red peppers or tomatoes valuable.

So colour is a decent proxy for certain plant compounds (like beta-carotene which we need for vision, skin health, immune system health, reproductive health and antioxidant activity in orange veg, anthocyanins in purple/blue foods), but it's not a rule. Some colourless foods are nutrient-dense, and some colourful foods are just colourful.

A truly healthy diet is built on variety, nutrient adequacy and whole foods, with the rainbow acting as a useful guide rather than the final goal.

"If you could only choose one nutrition principle, choose variety rather than colour. A diverse diet naturally creates a rainbow, but a rainbow doesn't always create a nutritionally complete diet."

My story, what I do

How the colours contribute

Colour | Key Nutrients/Compounds | Examples | Red | Lycopene, vitamin C | Tomatoes, watermelon, red capsicum
Orange/Yellow | Beta-carotene (vitamin A precursor), vitamin C | Carrots, pumpkin, sweet potato, mango
Green | Folate, vitamin K, magnesium, lutein | Spinach, kale, broccoli, peas
Blue/Purple | Anthocyanins, polyphenols | Blueberries, blackberries, purple cabbage
White/Brown | Potassium, selenium, sulfur compounds | Mushrooms, onions, garlic, cauliflower

Does eating a rainbow give you all nutrients?

No.

A rainbow of fruits and vegetables provides:

   Fibre 
   Vitamin C 
   Folate 
   Vitamin K 
   Potassium 
   Magnesium 
   Thousands of phytochemicals

But it may be low in:

   Vitamin B12 
   Vitamin D 
   Iodine 
   Calcium (depending on foods eaten) – inc 
   Iron 
   Selenium (in some regions) 
   Omega-3 fats (EPA and DHA) 
   Protein

What is more important than eating a rainbow?

For overall nutrition, a good hierarchy is:

1. Eat enough food

Without enough energy, nutrient deficiencies develop regardless of colour variety.

2. Eat a variety of whole foods

This is more important than colour alone:

   Vegetables 
   Fruits 
   Legumes 
   Whole grains 
   Nuts and seeds

3. Meet essential nutrient needs

The body requires:

   Protein (essential amino acids) 
   Essential fats (omega-3 and omega-6) 
   Vitamins 
   Minerals 
   Water

4. Then focus on colour diversity

Colour diversity helps maximise phytochemical intake and micronutrient variety.

The goal isn't colours, it is nutrient diversity. Colours are simply a visual shortcut that often helps people achieve it.

Eating the Rainbow: What Nutrients Each Colour Contributes

   Colour | Key Nutrients | Red | Vitamin C, folate (B9), potassium, lycopene
   Orange/Yellow | Beta-carotene (provitamin A), vitamin C, vitamin B6, folate (B9), potassium
   Green | Folate (B9), vitamin K, vitamin C, magnesium, potassium, riboflavin (B2)
   Blue/Purple | Vitamin C, vitamin K, manganese, anthocyanins, polyphenols
   White/Brown | Potassium, selenium, sulfur compounds, niacin (B3), small amounts of other B vitamins

B Vitamins Found in Rainbow Foods

   B1 (Thiamin) – legumes, peas, whole grains 
   B2 (Riboflavin) – spinach, mushrooms, almonds 
   B3 (Niacin) – mushrooms, potatoes, legumes 
   B5 (Pantothenic acid) – most vegetable mushrooms, avocado, sweet potato 
   B6 (Pyridoxine) – bananas, potatoes, capsicum 
   B7 (Biotin) – nuts, seeds, sweet potato 
   B9 (Folate) – leafy greens, asparagus, legumes, citrus fruits

Nutrients a Rainbow Diet May Be Low In

Even if you eat every colour every day, you may still not get enough:

   Nutrient | Why It May Be Low | Vitamin B12 | Found naturally almost exclusively in animal foods or fortified foods
   Vitamin D | Very few foods contain significant amounts- mushrooms when they are tanned and also fortified nutritional yeast
   Iodine | Depends on iodised salt, seaweed, dairy, seafood, or fortified foods
   Calcium | Fruits and vegetables alone may not provide enough
   Iron | Plant foods contain non-haem iron, which is less readily absorbed but eaten with vitamin c rich foo 
   Zinc | Plant sources contain phytates that reduce absorption
   Selenium | Depends heavily on soil content
   Omega-3 (EPA & DHA) | Primarily found in algae
   Protein | Can be low if legumes, nuts, seeds, and whole grains are not included

Different coloured plant foods contain different phytochemicals, vitamins, and minerals. By eating a variety of colours, you increase the range of nutrients and beneficial compounds you consume.

Eating the rainbow provides fibre, vitamin C, folate, vitamin K, potassium, magnesium and thousands of beneficial phytochemicals. It also contributes several B vitamins, particularly folate, B6, niacin and riboflavin.

However, a rainbow of fruits and vegetables alone may still be low in vitamin B12, vitamin D, iodine, calcium, iron, zinc, selenium, omega-3 fats and sometimes protein.

That's why eating the rainbow is an excellent strategy for nutrient diversity, but it is only one part of a nutritionally complete diet.

Recipe

Chickpeas and red rice warm salad

Chickpeas freshly cooked with rosemary

Red rice cooked  

Sweet potato baked in the oven

Steamed broccoli and kale

Yellow and red capsicum sauce

Roasted  1 yellow and red capsicum sauce

¼ cup soaked and roasted almonds

¼ cup water

2 tbsp balsamic vinegar

Salt and pepper to taste

Garnish

Sunflower and pepita seeds toasted

For the sauce blend everything in a blender and assemble the veggies, rice and chickpeas in a bowl and pour on some dressing and sprinkle with seeds  

Fun cooking tip

Freeze your beans.

Cook them using the bean cooking method and then freeze portions so next time you use them they are all ready – you just have to defrost them, which won’t take long at all

Hope you have a fabulous week and try to start eating more plates of highly nourishing food that can be seen as the rainbow.

With gratitude Veet