“Nourish, the Definitive Plant-Based Nutrition Guide for Families” is a book published in 2020 by Stanford-affiliated pediatrician Reshma Shah, MD, MPH, and well-known registered dietitian Brenda Davis. In January, there were three weekly columns based on this book about childhood nutrition and the three macronutrients — protein, fat and carbohydrates. The message was that with some basic nutritional knowledge and planning, a plant-based whole food diet supplies macronutrient needs at all stages of life and is “strongly associated with increased health and longevity.”
The series was put on hold during February (heart month), during which heart health-related columns appeared in this space. Let’s continue the childhood nutrition series with a column today about micronutrients, which are usually considered to be vitamins and minerals. There are 13 vitamins and at least 15 minerals that are essential for human health. Studies show that in general, meat-eaters have higher intakes of vitamin B2, zinc, selenium and iodine, while vegans have higher intakes of vitamin C, vitamin E, folate, magnesium, iron and copper.
Today we’ll discuss the micronutrients that can be inadequate in a total plant-based diet:
VITAMIN B12 is made by bacteria in dirt, and with treated water and pre-washed produce, most of us don’t eat much dirt these days. Animals get some dirt in their food, and the B12 is stored in their fat and muscle. Therefore, when people eat meat they get some B12, although if they’re age 50 or older absorption may be inadequate. Following are the recommended supplemental B12 doses in mcg (micrograms): 1-3 years 10 mcg; 4-8 years 25; 9-13 years 50; 14-49 years 100; 50 years and older 1,000; Pregnant and breast-feeding women 100. People with certain gastrointestinal conditions and those on medications such as metformin and acid blockers also need B12 supplementation.
iodine is a trace element necessary for production of thyroid hormone and many other aspects of health, including nervous system development of the fetus and infant. Even marginally low iodine levels in pregnant women can result in diminished IQ in their offspring. Important food sources of iodine are seaweed, fish, shellfish, dairy products and eggs. Iodine in plant foods is dependent on iodine content of soils where the plants are grown, which varies greatly. In order to prevent iodine deficiency, most countries require iodizing table salt (most salt added to processed food is not iodized). Too much iodine also causes problems. It’s important to know that iodine content of seaweed is variable, and Hijiki seaweed should be avoided due to arsenic contamination. Vegans of all ages who aren’t eating seaweed need to take iodine supplements. The following age-related daily dosages are recommended: age 0 to 6 months 110 micrograms; 7-12 months 130; 1-8 years 90; 9-13 years 120; 14 years and older 150; pregnant women 220; breast feeding women 290 (infants and babies on breast milk don’t need additional supplementation if the mother is on iodine supplement).
ZINC is an essential mineral needed for normal growth and development of the fetus and throughout life. Protein-rich foods such as shellfish, meat, legumes, tofu, nuts, seeds and whole grains contain the most zinc. Zinc in plant foods can be less bioavailable than that in animal foods, but nevertheless, zinc deficiency is rare in developed countries. For plant-based children, zinc supplementation can be considered, and the following are the recommended dosages in micrograms: 0-6 months 2 mcg; 7 months to 3 years 3; 4-8 years 5; 9-13 years 8; females 14-18 years 9; females 19 and older 8; males 14 and older 11; pregnant women 11; breastfeeding women 12. Too much zinc can be harmful, so more is not better.
For the most part, people of all ages on a plant-based diet will be getting vitamins and minerals the way we’re meant to get them — through the food we eat. However, exceptions are B12, iodine and perhaps zinc. These supplements can be purchased across the counter in pharmacies, or can be taken as part of a multivitamin/mineral product (check the label to be sure you’re getting the recommended doses).
The “Nourish” book is available on Amazon, and is very a very useful guide if pregnancy is being contemplated and for parents of children of all ages.
Dr. Feinsinger is a retired family physician with special interest in disease prevention and reversal through nutrition. Free services through Center For Prevention and The People’s Clinic include: one-hour consultations, shop-with-a-doc at Carbondale City Market and cooking classes. Call 970-379-5718 for appointment or email firstname.lastname@example.org.