Recently a good friend of mine told me that she was diagnosed with anemia. She has been vegan for as long as I have known her (at least five years) and is the first vegan I’ve met who actually had a mineral deficiency of any kind. While I can’t go into specifics, I do know she follows a mostly health promoting lifestyle. Besides generally eating well she is also an accomplished Ironman athlete. Some of the symptoms she felt included general fatigue and dizziness but other signs of anemia include: pale skin, rapid heart beat, shortness of breath during exercise, headaches, insomnia, and muscle cramps.
She reached out to me for a little advice and happy to oblige I started doing a little more in-depth research. This is what I found.
The main function of iron in our body is to create hemoglobin, which helps facilitate red blood cell health. An adequate iron level is of paramount importance as it ensures the cells are able to deliver oxygen-rich blood throughout the body. Iron also plays a role in building blood proteins needed for food metabolism, digestion, and proper circulation.
First, while my friend is anemic, meaning she does not have enough iron in her system, having too much iron is equally dangerous – watch for a fuller post on this subject in the future. While it is relativity rare to be diagnosed, iron toxicity typically occurs in those who eat meat. This is because of the type or “quality” of iron in animal vs. plant foods. People obtain iron from either eating plants or from eating animals that have been fed plants. It is then absorbed into their bodies through the upper gastrointestional tract. Plant foods contain what is known as non-heme iron. Animal foods contain non-heme iron but also has whats known as heme iron or “blood iron.” Traditionally, we our told that heme iron is more easily absorbed by our bodies and therefore of a higher quality, but that view is starting to be questioned as excess iron has increasingly been linked to Alzheimer’s disease, a double digit increased risk in colorectal cancer, type II diabetes, and coronary heart disease. Heme iron intake has also been associated with increased risk of stroke, gestational diabetes, gallstones, and cancers of the prostate, lung, stomach and kidneys, among others.
Our bodies are remarkable. Because the human body doesn't have a mechanism to rid itself of excess iron, we evolved a way to regulate its absorption. When our bodies have sufficient storage levels of iron approximately 5% percent of the iron present in food is absorbed, when a person is iron deficient, then the amount absorbed from the foods eaten can increase by as much as 20%. However, studies have found that the body has a much more difficult time regulating the absorption of heme iron, making iron toxicity or iron overload much more possible.
Now, back to the original topic of anemia. I want to stress that it is very possible to become anemic on any type of diet. Vegetarian’s levels of Hemoglobin, which reflects the amount of iron in the blood, are comparable to those in people who eat flesh. In a review by Craig McPherson, M.D., he stated that while iron stores may be lower in vegetarians, there is no reported increase in incidence of iron deficiency anemia. In fact, iron reduction has been shown not only to decrease the risk of getting various types of cancer by 35%, but anemia has actually been found less frequently overall in those who eat a strict vegetable based diet than those on the Standard American Diet – this is potentially caused by the consumption of large amounts of dairy which bind and inhibit the body from absorbing iron.
Back in July when I had my blood tested, my hemoglobin levels were found to be in the ideal range so I don’t overly concern myself with iron (Hemoglobin A1C: 5.1 which also puts me at a lower risk of diabetes). That said many plant foods that I regularly consume are high in iron. Dark leafy greens and dried beans are perhaps the best sources of non-heme iron. Not only is kale, collards, and spinach all high in iron but they also contain vitamin C, which helps the absorption of non-heme, and are overall, healthy for everyone to consume. In fact, per 100 calories, cooked spinach has more than 15x the amount of iron than a steak! Soybeans, lentils, tofu are also all excellent sources - and all higher in iron than steak per 100 calories-and are accessible and affordable.
However, sometimes just eating foods high in iron won’t be enough, as my friend recently found out. The good news is just because she was diagnosed as being anemic, doesn’t mean she needs to turn to meat. Nor does it necessarily mean she should start gulping iron supplements. Dr. Michael Greger of nutritonfacts.org suggests that those who are diagnosed with anemia talk with their physician about first trying to get their blood hemogloblin levels up through diet alone, because a recent study found an increase in oxidative stress in the body.
Luckily, there are many things we can do to help encourage our bodies to absorb non-heme iron found in our food.
As I mentioned above, vitamin c rich foods helps our bodies absorb non-heme iron. While dark leafy greens have both iron and vitamin c, if you are eating a food that is lower in vitamin C such as chickpeas, it is best if you include a food higher in vitamin c with it such as bell pepper, citrus fruits, broccoli ect. It’s also not a bad idea to avoid taking in tea or coffee as both can block iron absorption.
Another slick trick to help improve the bioavailability of non-heme iron is to prepare your dish with foods such as garlic and onion. The allium family of vegetables foods have phytonutrients that help promote iron absorption. Also steaming your dark leafy greens before eating them can also help improve your bodies iron absorption.
While cooking with cast iron has also been shown to increase the amount of iron content in foods, our bodies are less able to manage the absorption of that type of iron - making it less than ideal for those already with healthy storages of iron.
Below is a chart of plant foods high in iron:
Food Amount Iron (mg)
Soybeans, cooked 1 cup 8.8
Lentils, cooked 1 cup 6.6
Spinach, cooked 1 cup 6.4
Tofu 4 oz 4.7
Chickpeas, cooked 1 cup 4.7
Swiss Chard, cooked 1 cup 4.0
White Potato 1 large 3.2
Quinoa, cooked 1 cup 2.8
Pumpkin Seeds 1 cup 2.1
Pumpkin Seeds 1 cup 2.1
Raisins ½ cup 1.6
Kale, cooked 1 cup 1.2
Broccoli, cooked 1 cup 1.1
Source: USDA Nutrient Database for Standard Reference.
Brazier, Brendan, Thrive: The Vegan Nutrition Guide to Optimal Performance in Sports and Life. 2007.
Cook, J.D. “Adaption in Iron Metabolism.” Journal of American Journal of Clinical Nutrition. February, 1990
McDougall, Craig, M.D. “Letter to the Editor: Plant Based Diets Are Not Nutritionally Deficient.” The Permanente Journal. Spring; 17.
“The McDougall Newsletter.” Vol 12, Issue 8. The Asian Paradox: End of the Line for Low Carb Diets? Literature Review
Hunt, JR. “Bioavailablitliy of iron, zinc, and other trace minerals from vegetarian diets.” American Journal of Clinical Nutrition. Sept 2003; 78.
Pulde, Alona, M.D. and Matthew Lederman, M.D. Keep it Simple, Keep it Whole: Your Guide to Optimum Health. 2009.
As always the information presented in this blog is for educational purposes only. It should not be considered as specific medical, nutritional, lifestyle, or other health-related advice.