Minerals

Iron

The term “anemia” often gets tossed around by omnivores who are concerned that their newly-vegan friends will become anemic without slabs of red meat. Furthermore, most people automatically assume anemia is related to iron deficiency, but anemia can in fact be caused by deficiencies of other nutrients, such as vitamin B12, folate, vitamin E, and copper. Here I’ll just discuss some things to consider about iron. Iron is involved in energy production, thyroid hormone production, transport of oxygen, immune function, and DNA synthesis. Numerous chronic diseases and conditions put individuals at risk of iron deficiency such as Celiac disease, bariatric surgery / gastrectomy, hypothyroidism, COPD, chronic kidney disease, Crohn’s, H. pylori infections, ulcerative colitis, and heart failure. Medications (proton pump inhibitors, anticonvulsants, metformin, chemotherapy) can also decrease iron absorption or utilization. 

The recommended daily allowance (RDA) for iron for vegans is 1.8X the amount recommended for omnivores because vegans must get iron exclusively in the form of non-heme iron (animal products contain heme iron which is absorbed a bit easier). Technically this means vegan women should get 32 mg/d, a high bar for women to obtain and one I think is too high. The tolerable upper intake level is 45 mg/d for adult men and women which isn’t much higher than the 32 mg/d recommendation. Some people (myself included) are genetically predisposed to have higher than normal levels of iron which will likely show up on a blood test, so care must be taken not to overload.   

Measuring iron stores

Investigating anemias and iron status isn’t always as simple as just looking at hemoglobin/hematocrit, as those are the last markers to change when iron stores are low. One of the best markers of iron status is ferritin (an iron storage protein), but note the wide reference range labs may use. Always obtain a copy of your labs from your doctor to check your values to make sure you’re not at the very bottom or top of the reference range. Ferritin can skyrocket in the presence of inflammation so it’s not always reliable. Your doctor might run an iron panel measuring things like the amount of free iron circulating in your blood and the affinity of your cells for iron.  

Getting enough iron

If your doctor recommends getting iron through food and not supplementing, great vegan food sources of iron are: bran flakes, cream of wheat, dried prunes, spinach, tofu, extra dark chocolate (yes!), soybeans, and dried beans or lentils. Check out this post for other food sources of iron. If you’ve gone through a thorough workup and your doctor has uncovered an iron-deficiency anemia, they may prescribe a specific dose of iron to correct the deficiency. Certain forms of iron can be quite constipating and harsh on the digestive tract though, so if you can’t tolerate one form do try another such as ferrous bisglycinate or look for a label that indicates “gentle,” “well-tolerated” or controlled-release forms.  

Bottom line: Iron status can be a tricky beast in the setting of veganism, chronic disease, medication usage, and genetic predisposition. If you don’t need to restrict iron, focus on the iron-containing foods above and get labs checked yearly. Your doctor should let you know if you either need to restrict iron or if you need to supplement it.      

Sources and Further information: 

Vegetarian Resource Group

PCRM Nutrition Guide  

Solgar Gentle Iron 

ConsumerLab

Iodine

Iodine is one of the trace elements that plays a key role in thyroid function and metabolism. It’s a special concern for vegans, but it’s also one of the most common nutrient deficiencies worldwide. Somewhere between 1.5-2 billion people around the world likely have suboptimal intake, mainly due to variable soil content and lack of salt fortification. Adults need 150 mcg daily, and pregnant women need 220 mcg daily because deficiencies can lead to growth retardation and neurodevelopmental issues in the baby. In adults, deficiencies can manifest as goiter (an enlarged thyroid gland) and hypothyroidism because iodine molecules are essential parts of thyroid hormones. Interestingly, too much iodine can also increase the risk of hypothyroidism and autoimmune thyroiditis (Hashimoto’s). 

Where do vegans get iodine from? The few notable vegan sources of iodine are sea vegetables (such as kombu, wakame and dulse) and iodized salt. Omnivores get it from seafood, and it’s also found in significant amounts in milk partially because iodine solutions are used as “teat dips” to clean cow’s udders. Personally I don’t want to be getting my trace elements from remnants of a cleaning solution. Unfortunately plant milks are not reliable sources of iodine and many people struggle to eat sea vegetables. If you’re not salt-sensitive and don’t have blood pressure issues, it’s worth using iodized salt: ¼ tsp provides 75 mcg iodine, half the daily recommendation for non-pregnant adults. 

Processed foods, while they may be extremely high in sodium, usually don’t contain iodized salt and are not a reliable source. Sea vegetable supplements and supplements that feature “iodine from kelp” are also unreliable: ConsumerLab reports that half of the kelp supplements they tested contained twice the amount of iodine listed! 

How do I test my iodine status? It’s tricky. Medscape reports that “no test can reliably diagnose iodine deficiency in individual patients.” Population-level iodine status is measured via urinary iodine, but it’s been found to be inaccurate on individual levels because values fluctuate so much with daily intake. One option is a 24-hour urine collection, but that’s cumbersome and again depends on recent intake. Because deficiencies will show up mainly as thyroid issues in adults, it’s very important to have complete thyroid labs measured yearly.  

Bottom line: For my vegans, if you’re not salt-sensitive, use iodized salt and not kosher or Himalayan sea salt. If you like sea veggies, go for it, but avoid kelp. Otherwise I recommend getting iodine as part of a multivitamin/mineral as either potassium iodide or sodium iodide (aim for 100-200 mcg daily).  

Source and Additional Reading: American Thyroid Association 
Gropper, S. A. S., Smith, J. L., & Groff, J. L. (2009). Advanced nutrition and human metabolism. Australia: Wadsworth/Cengage Learning.