Bioavailable Nutrients
Why Animal-Sourced Foods are Better than Plants
Many plants contain compounds like trypsin inhibitors, phytic acid, and lectins, which hamper your body’s ability to break down proteins and absorb key minerals like zinc, magnesium, and calcium. Some of these compounds can be reduced by soaking, boiling, and fermenting, but can still pose a threat if consumed in high amounts.
Lectins, for example (found in high amounts in grains) have been causally implicated in gut dysfunction and autoimmunity. Lectins damage the gut barrier, causing it to become permeable or “leaky”, which can allow toxins that an intact gut barrier would normally ward off to enter your bloodstream, resulting in systemic inflammatory responses long-term. Cooking, fermenting and other forms of “processing” however, can reduce the amounts of antinutrients in plant foods.
For amino acids in particular, we use the Digestible Indispensable Amino Acid Score or “DIAAS” to assess protein quality. DIAAS samples come from the last part of the small intestine known as the ileum, and account for anti-nutritional factors when measuring protein absorption. High quality proteins are both complete proteins (i.e. they contain all 9 essential amino acids) and bioavailable proteins (meaning the amino acids inside of them are actually absorbed by YOU).
Notice how even the plant protein ISOLATES rank lower than all of the animal foods… and that’s just for protein!
When it comes to vitamins and minerals, most of them are much easier, more practical, and safer to acquire through animal foods than plant food sources.
Vitamins and Minerals
Let’s take zinc, for example. The most potent chelator of zinc, phytic acid, is found in most grains and legumes. Zinc is required for enzymes to function, especially those involved in DNA repair, and stabilizes cell membranes by preventing lipid peroxidation and forming complexes that scavenge free radicals. When phytic acid binds zinc, it forms an unabsorbable complex that your body cannot use. This makes sense, because a plant that is stuck in the ground with no observable defenses does NOT want you to be getting bioavailable nutrients from it! But it doesn’t just stop at zinc or phytic acid. Both phytic acid and oxalic acid (which is found in high amounts in dark leafy greens and nuts) can bind to zinc, calcium, magnesium, copper, and iron, preventing their absorption. Still think that raw green smoothie is doing you any good?
Animal proteins and fats, on the other hand, have been shown to increase the bioavailability of important minerals like zinc, as well as the fat soluble vitamins, A, D, E, and K. In fact, the only source of K2 from plants is from fermented vegetables like natto, whereas K2 is found ubiquitously in animal foods, and is highest in dairy and liver.
Read the full article on the Sustainable Dish website.
Flawed ‘Food Compass’
Previously, I wrote about the flawed “Food Compass” report by Tufts Nutrition School. It now seems others are picking this up:
Flawed Food Compass metric could misguide tax and investment decisions
“The risk is that multinationals' ultra-processed products are labelled with a stamp of approval”
Flaws in a new food metric could hinder public health efforts and misguide tax and investment decisions across the US and other markets, a global team of scientists has found. They are concerned about the Food Compass Nutrient Profiling system, published in Nature Food in October. It rates the cereal Frosted Mini-Wheats and chocolate-covered almonds in the highest score bracket, “to be encouraged”, while relegates millet, whole wheat bread, boiled eggs and skinless chicken breast in the lower bracket “to be moderated”.
The system could potentially displace nutritious foods in low- and middle-income country markets, to promote less healthy, ultra-processed products in favour of local items, the scientists say.
“The lack of attention to nutrient density is problematic, particularly of nutrients connected to bigger public health issues, like iron for example. In the US about 20 per cent of women aged 15 to 49 are iron deficient,” Ty Beal.
Read the full article in Quota here.
Diana Rodgers, RD