plant food know-how


Eating a rainbow of colours and lots of vegetables is not only great for you, its also fashionable as more and more people adopt the vegan lifestyle. And with good reason: plant based diets are without doubt the healthiest lifestyle choice

  • Vegetables are incredible nutrient powerhouses
  • Plant foods contain powerful cancer busting, anti-aging, and anti-inflammatory phytonutrients (find out more in my post here)
  • Plant foods contain wide ranging health promoting effects fiber (which i mention in my post here).

However there are rules to the plant playground – plant compounds that you need to be aware of. In this post I delve into what that means to us as we eat, and how we can harmonise with what we eat in greater ways.

Phytates and Lectins in legumes, grains and nuts

These foods are plant seeds that are designed by natural evolution to withstand digestion (or even, in the case of Lectins, to aggravate the GI tract). Soaking and sprouting is the most effective method for de-activating these plant protection mechanisms – which i explain in my post here

Cabbage family vegetables (such as kale, collards and spinach)


  • contain Goitrogens, compounds (isothiocyanates) that block the utilization of iodine by the thyroid
  • interferes with thyroid hormone production if consumed in large amounts (more than 4 servings per week) or if they are consumed raw
  • cooking helps to inactivate thyroid disrupting compounds
  • bottom line
    • if you have an existing iodine deficiency, extra iodine can be sourced from kelp and seaweeds and iodized salt
    • if you have hypothyroidism symptoms it is best to strictly limit or avoid these vegetables
    • if you regularly eat cabbage family plants, ensure you cook them


  • in many vegetables, especially leafy greens as well as nuts
  • foods high in oxalates bind to Calcium in the body to form crystals the body cannot absorb and these crystals are excreted in the urine
  • if those crystals are not excreted, they collected in the kidneys to form kidney stones
  • the overall effect of oxalates is to
    • promote the loss and excretion of the vital mineral Calcium from the body
    • increase the risk of kidney stones
    • increase the risk of Calcium deficiency
  • Foods highest in oxalates
    • include beets, many green leaves (like spinach), some beans (like Navy beans), some nuts (like Brazil nuts)
    • cooking does NOT destroy oxalates
  • bottom line
    • oxalates are a concern if you have
      • Calcium deficiency, an enhanced need of Calcium (eg you are pregnant), are at risk of kidney stones
    • in these cases limit the consumption of foods that contain oxalates
    • check foods on this site – all of the foods on this site have a rating if oxalate content in them is moderate or high
  • For further information about which foods are highest in oxalates, see this comprehensive article about oxalates from the website WH Foods

Nightshade family vegetables (such as white potato, bell peppers, egg plant, goji berries)



  • have been linked to a worsening of arthritic symptoms
  • bottom line – strictly avoid all nightshade family plants if you have arthritris

Potatoes and Solanine Poisoning

  • Potatoes that show signs of greening, sprouting, rotting, or physical damage should not be eaten because of the high concentrations of solanine
  • Potatoes naturally produce solanine as a defense mechanism against insects, disease, and predators and can occur naturally in the any part of the plant, including the leaves, fruit, and tubers
  • Solanine is very toxic even in small quantities and is primarily displayed by gastrointestinal and neurological disorders (eg nausea, diarrhoea, vomiting, stomach cramps, headaches and dizziness)
  • Most solanine occurs in the skin or just under the skin of potatoes where potatoes that have been exposed to light and started to green. Solanine is also present in potato shoots
  • Peeled potatoes have been found to contain 30-80% less solanine than unpeeled potatoes

bottom line:

  • green potatoes should always be peeled if they are to be used at all
  • cut away and compost any shoots or green parts

A quick request …

This post and this blog is dedicated to my fundraising to support Alzheimer’s Society. Please click on the link below to find out more and to make a donation today! JustGiving - Sponsor me now!

Adapted from:

Murray, M. (1998). The complete book of juicing. Roseville, CA: Prima publishing

Haas, E. (2006). Staying Healthy with Nutrition. Berkeley, Ca. Celestial Healing Arts.

Murray, M. (2005). Encyclopedia of Healing Food. New York, N.Y.: Atria Books


A comprehensive article about oxalates from the website WH Foods

A guide to the oxalate content of foods from the Children’s Medical Centre in Dayton

Noonan, S. C., & Savage, G. P. (1999). Oxalate content of foods and its effect on humans. Asia Pacific J Clin Nutr, 8(1), 64-74

Savage, G. P., Vanhanen, L., Mason, S. M., & Ross, A. B. (2000). Effect of Cooking on the Soluble and Insoluble Oxalate Content of Some New Zealand Foods. JOURNAL OF FOOD COMPOSITION AND ANALYSIS, 13(201), 206

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