The Side Effects of Being Vegan — and How to Avoid Them


Vegan diets, which do not include any animal products (such as meat, fish, dairy, or eggs), have been increasing in popularity over the years

1. Vitamin B12 deficiency

Why is this Important?

Vitamin B12 is a nutrient required for energy metabolism, nerve signal transmission, and activation of folate (a nutrient needed for DNA synthesis and red blood cell health). The special thing about vitamin B12 is that it is found ONLY in animal foods! With that in mind, it might not come to you as a surprise that vitamin B12 is a nutrient of concern to those following vegan diets. Vitamin B12 deficiency can result in macrocytic anemia, and patchy nerve cells, causing poor nerve signalling.

 What to do About it

Adequate vitamin B12 intake can be achieved through:

  • Fortified vegan-friendly alternatives,
  • Nutritional yeast, or 
  • Supplementation (talk to your physician or friendly neighbourhood RD!). 

2. Digestive Issues

Why is this Important?

A great thing about plant-based diets is that individuals following them often consume increased amounts of fruits, vegetables, and whole grains, which results in an overall increase in fibre intake. Adequate fibre intake is not only extremely important for your gastrointestinal health by moving things along (if ya know what I mean) and acting as a prebiotic to nourish your gut flora, but it also slows glucose absorption and soluble fibre even decreases blood cholesterol! However, drastic changes in fibre intake and excess fibre intake in your diet can result in abdominal discomfort and gassiness, impaction or constipation, and decreased mineral absorption. 

What to do About it

The good news is, excess fibre is usually something you don’t need to be worried about! By doing the following, you can prevent these not-so-fun side effects. 

  • Increase fibre gradually 
  • Increase your water intake when increasing fibre intake.
  • Be patient — your gut will get used to increased consumption of foods such as beans or legumes over time, which means less discomfort and flatulence!

3. Iron Deficiency

 Why is this Important?

Iron is an essential nutrient often associated with protein foods such as liver, meat, and legumes. Iron is not only needed to make hemoglobin to carry oxygen in your blood, but is also used to synthesize enzymes and needed to release energy from the food you eat. Anemia (the lack of healthy red blood cells) can be caused by long-term iron deficiency, resulting in low oxygen capacity in the blood, decreased energy production, fatigue, and impaired immune function. 

What to do About it

  • Iron from plant foods (non-heme iron) is less bioavailable than the iron found in animal foods (heme iron). It is usually recommended that vegans and vegetarians consume 1.8x the recommended dietary allowance (RDA)  per day, to prevent iron-related side effects. 
  • Enhance iron absorption by consuming your non-heme iron with vitamin C (like in an orange or strawberries).
  • Reduce or avoid impairing iron absorption by spacing out certain nutrients and not taking them within 1-2 hours of taking your iron supplement. Inhibitors include calcium, tannins in coffee/tea and phytic/oxalic acid found in nuts, seeds, and raw leafy greens.
  • Choose iron-rich plant foods such as legumes and lentils, pumpkin, hemp, and flax seeds, leafy greens, or fortified grain products.
  • Bonus tip: you can boost your intake of iron by cooking in a cast-iron pan!

4. Lack of energy

Why is this Important?

From a whole, unprocessed-food standpoint, plant foods are generally less calorie dense when compared to animal foods. As a result, by following a plant-based diet, it is not uncommon that you would be consuming fewer calories than if you were eating a diet that included animal foods. Although getting enough micronutrients such as vitamins and minerals is important, it is just as important to be getting enough calories through your macronutrients (carbs, fats, and proteins)! If you aren’t getting enough calories you may feel fatigued and lethargic. 

What to do About it

Many plant foods can be high volume but low calorie, meaning they may fill you up quickly but you may start feeling peckish again soon after eating. The key to getting around this is to:

 By eating meals balanced with proteins, carbs, and fats in addition to your nutrient dense, low calorie veggies, you will feel fuller for longer, while satisfying your body’s caloric needs. However, if you feel hungry, that is your body’s way of telling you that you may need more food, and that’s where the snacking comes in! Plan ahead and have snacks such as crackers and hummus, apple slices and peanut butter, or some dried fruit and nuts on hand for the little midday pick-me-up that you deserve.

5. Feeling Restricted

Why is this Important?

Sometimes you may feel like you are stuck with only a few food options, but remember, eating is all about enjoying what makes you feel good and what nourishes your body and a vegan diet is no different! It is important to be in tune with your own personal needs — if you feel like you are becoming stressed over what you are eating or become preoccupied with food, you may be restricting yourself too much

What to do About it

The good news is, however, that nowadays, there are countless vegan options and vegan substitutes in restaurants and grocery stores.

  • By exploring your local community, you may be surprised to find just how many delicious vegan-friendly options there are! 
  • Don’t be afraid to try new things, whether it be a new vegan restaurant, animal-product substitute, or vegan-friendly recipe you find online.
  • Remember that veganism is much more than salads and tofu!

Check out our website and blog for some amazing vegan recipes such our delicious almond, prune and chocolate muffin, and more discussions regarding health and wellness!

Blog Contributor

This blog was written with the help of UBC nutrition student, Gilbert.

References:  [June 6th, 2019]

Eight Vegan Diet Dangers (One Is Irreversible)  [June 6th, 2019]

6 Science-Based Health Benefits of Eating Vegan [June 6th, 2019]

7 Possible Side Effects of Going Vegan

Plant-based diet got you feeling bloated? Here’s what to do about it. [June 13th, 2019]

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