Along with "How old are you?", "What's your favourite food?" is a major classic when it comes to small talk topics with children (probably because they haven't yet graduated to the pure sophistication of topics like the weather and "How was your weekend?"). Typical kid answers to this have got to be pizza and ice cream, but pretty much anything with a low nutritional status tends to fit the bill.
That's why it's always been a complete mystery as to why my personal favourite food as a child was broccoli. What kid even LIKES broccoli, let alone claims it as their favourite food? But I craved it and simply couldn't get enough. And come to think of it, when I entered my teens and took on responsibility for cooking family meals, I put broccoli in EVERYTHING (much to my sister's horror).
As an adult, this childhood love of broccoli always perplexed me. I won't say that wondering about it kept me up nights, but it was certainly one of those bizarre and curious unsolvable mysteries... Until, that is, the fateful day when I received my first genetic nutrition test results, and I learned that I am a null genotype for GSTM1 and GSTT1.
You see, these two very interesting genes called GSTM1 and GSTT1 code for a very particular enzyme called glutathione S-transferase that's produced in the liver, and this enzyme detoxifies things like carcinogens, therapeutic drugs, environmental toxins, and products of oxidative stress. Think of it as an anti-cancer enzyme--it's a pretty important little molecule for keeping us healthy! But what's really interesting is that lots of us, me included, have what is called a 'null genotype'--we're completely missing the genes needed to produce the enzyme. Interestingly, the percentage of us missing the enzyme varies across the population and tends to be higher in Caucasians and Asians than in Africans, ranging for example, from 21.7% in Nigerians and 43% in French to 58.3% in Chinese. (Alshagga et al 2011) But that's still perhaps at least a third of the human population who are missing these genes, which is a LOT of people.
Whoa! But if we can't produce the enzyme, then we can't detoxify really dangerous things in our bodies, right?! And without the ability to detoxify these things, we'd most likely die pretty early on of diseases linked to the build up of and damage caused by these dangerous molecules.
Except... The ability of our genes to sustain life always has an explanation in evolution, and the answer to how lots of people can exist without these genes and still thrive is down to one thing: cruciferous vegetables.
What's a cruciferous vegetable? It's exactly what kids tend to turn their nose up at and refuse to eat! Broccoli, cabbage, cauliflower, kale and about 15 other gorgeous vegetables. And they're able to keep us 'null genotypes' alive and kicking because they contain within them the ingredients for a brilliant compound that, when eaten, replaces the missing enzyme in our bodies and allows us to detoxify without it. Incredible.
When I found out that I'm one of these 'null genotype' people, that's when the mystery of my favourite childhood food, broccoli, unraveled before me. My craving was undoubtedly born out of a physiological necessity for the compounds contained within cruciferous vegetables.
My recommendation to anyone missing these genes is to aim for 1 serving of raw curciferous vegetables daily. Since I also normally recommend a minimum of 7 servings of vegetables a day, it makes up a relatively small percentage of overall vegetable intake. And even if you're not missing the GSTM1 and GSTT1 genes, cruciferous vegetables are an important part of everyone's diet due to their sulfur-containing compounds and will help support long-term vibrant health!
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