Plant-Based Nutrition: Episode # 4 – Minerals

Wondering about how to boost your intake of key minerals on a plant-based diet!? 

In our previous episode of the Plant-Based Nutrition series we focused on how to optimize the intake of vitamins D and B12 in your diet. In this episode we’ll explore how to overcome mineral deficiencies on a plant-based diet.

Although all essential minerals offer unique benefits, below are 3 key minerals that you should be especially mindful of on a plant-based diet: 

1. Calcium

Calcium serves numerous important functions in the body. It is crucial for maintenance of healthy bones and teeth, stimulating muscle contractions, nerve functioning, regulating blood pressure, blood clotting, and is required for a healthy immune system [1]. 

Long-term calcium deficiency can lead to many health consequences including bone loss or osteoporosis and increased risk of fractures [2,3]. 

The recommended dietary allowance (RDA) of calcium per day is 1,000 mg (milligrams) for young adults and 1,200 mg for those over 50 years of age [4]. 

Many people think dairy is the only source of calcium, however, it is also naturally present in many plant-based foods. With careful planning, people following a plant-based diet can easily obtain the recommended levels of calcium! 

Some calcium-rich plant-based sources include: 

• Calcium-set tofu (prepared with gypsum/calcium sulfate as a coagulant; make sure to check the ingredients list for this!)
• Calcium-fortified plant-based beverages (ex. soy milk and orange juice) 
• Black beans
• Collard greens
• Bok-choy
• Kale
• Sesame seeds and tahini
• Broccoli 

If you’re not getting adequate levels of calcium through your diet alone, supplementing may be helpful. 

Also, evidence suggests that vitamin D helps improve calcium absorption and taking both vitamin D and calcium together is more beneficial to bone health [5]. Read all about vitamin D here! 

2. Iron

Iron is another important mineral to pay extra attention to in your diet. This mineral is a central part of hemoglobin – the molecule in red blood cells that transports oxygen through your body. Without iron, your body cannot produce healthy oxygen-carrying red blood cells. This leads to a condition called iron deficiency anemia, which tends to be more prevalent in children, vegetarians and females who are pregnant or have heavy periods [6,7]. 

Iron is also essential for energy metabolism, healthy immune function as well as normal brain development and growth in children [8].  

The RDA for iron is 8 mg for adult males and 18 mg for adult females! With greater amounts recommended during pregnancy and for vegetarians or vegans [7].

Dietary iron is present in 2 forms: heme and nonheme. Plant based sources contain only non-heme iron, whereas animal sources of foods contain both forms. However, non-heme iron is less readily absorbed in the body compared to heme iron. For this reason, the RDAs for vegetarians are 1.8 times higher than people who consume meat [7]. 

Luckily, you can get all the iron you need from a well-planned plant-based diet. Here are a few good sources of nonheme iron: 

• Iron-fortified breakfast cereals
• Tofu 
• Beans
• Lentils
• Dark green leafy vegetables (spinach, kale)
• Dried fruit (raisin, apricots)
• Nuts and seeds
• Enriched rice or bread

And of course, if you are not getting enough iron from foods, supplementation may be effective, especially for those who are at risk of iron inadequacy. 

One tip to keep in mind is that adding foods rich in vitamin C to your diet can help enhance the absorption of iron [9]. Sources of vitamin C-containing foods include citrus fruits, bell peppers and strawberries. So try pairing your iron-rich foods with foods or beverages containing vitamin C to help your body absorb iron more effectively. 

3. Zinc 

Zinc is abundantly present in the tissues of the body. It is involved in immune function and cell metabolism and has many structural and regulatory roles in the body. Zinc is also critical for  normal growth and development during rapid growth stages such as pregnancy, childhood and adolescence [10]. 

The daily RDA of zinc for adults is 11 mg for males and 8 mg for females [11]. 

One consideration is that the bioavailability of zinc from plant-based diets is lower than non-plant-based diets. Plant-based sources of zinc contain inhibitors of zinc absorption. Therefore, those following a plant-based diet often have greater daily RDAs of zinc as they are more prone to risk of deficiency [11]. 

The good news is that with good planning, you can obtain all the zinc you require from eating a well-balanced plant-based diet. Using simple preparation techniques to increase the bioavailability of zinc can help reduce the risk of deficiency of this nutrient. For example, consuming leavened whole grains (such as sourdough, ) as opposed to unleavened grains (e.g. crackers), can help break down zinc absorption inhibitors [12]. When cooking at home, simply pre-soaking whole grains and dried legumes is also another effective way to enhance zinc absorption. Just make sure to discard the soaking water before eating or cooking[12]! 

Other good dietary sources of zinc include:

• Tofu
• Tempeh
• Seitan
• Legumes
• Nuts and seeds
• Fortified breakfast cereals 
• Fortified plant-based milks

Modest supplementation of zinc may also be helpful in achieving the RDAs through plant-based sources [11]! 

Take-away 

It is important to pay extra attention to calcium, iron and zinc on a plant-based diet to avoid becoming deficient in them! 

Given the above considerations, carefully planned and balanced plant-based diets can provide adequate levels of these minerals and help optimize nutrient status! 

Remember to include varied foods that help enhance the bioavailability of these minerals for better absorption in your body! 

References

1. Vannucci, L., Fossi, C., Quattrini, S., Guasti, L., Pampaloni, B., Gronchi, G., Giusti, F., Romagnoli, C., Cianferotti, L., Marcucci, G., & Brandi, M. L. (2018). Calcium Intake in Bone Health: A Focus on Calcium-Rich Mineral Waters. Nutrients, 10(12), 1930. 
2. Iguacel, L., Miguel-Berges, M.L., Gómez-Bruton, A., Moreno, L.A., Julián, C. (2019). Veganism, vegetarianism, bone mineral density, and fracture risk: a systematic review and meta-analysis. Nutrition Reviews, 77(1), 1–18. 
3. Smith, A.M. (2006). Veganism and osteoporosis: A review of the current literature. International Journal of Nursing Practice, 12(5), 302-306. 
4. Health Canada. (2010). Dietary Reference Intakes. 
5. National Institutes of Health (2020). Calcium. Office of Dietary Supplements. 
6. Pawlak, R., Berger, J., & Hines, I. (2016). Iron Status of Vegetarian Adults: A Review of Literature. American journal of lifestyle medicine, 12(6), 486–498. https://doi.org/10.1177/1559827616682933
7.  National Institutes of Health (2020). Iron. Office of Dietary Supplements. 
8. Beard, J.L. (2001). Iron Biology in Immune Function, Muscle Metabolism and Neuronal Functioning. The Journal of Nutrition, 131(2), 568S-580S.
9. Hurrell, R., & Egli, I. (2010). Iron bioavailability and dietary reference values. The American Journal of Clinical Nutrition, 91(5), 1461S-1467S.
10. Roohani, N., Hurrell, R., Kelishadi, R., & Schulin, R. (2013). Zinc and its importance for human health: An integrative review. Journal of Research in Medical Sciences, 18(2), 144–157.
11. National Institutes of Health (2020). Zinc. Office of Dietary Supplements.
12. Gibson R.S., Heath, A.M., & Szymlek-Gay, E.A. (2014). Is iron and zinc nutrition a concern for vegetarian infants and young children in industrialized countries? The American Journal of Clinical Nutrition, 100(S1), 459S–468S.