The increasing popularity of vegetarian and vegan diets has sparked interest in their potential health benefits. While these diets can offer advantages such as weight loss, improved blood sugar control, and a reduced risk of heart disease and certain cancers, it's crucial to understand the potential pitfalls that can lead to fatigue. This article explores the common causes of fatigue in vegetarians and vegans and provides practical solutions to address them.
Plant-Based vs. Vegan: Defining the Terms
It's important to distinguish between plant-based and vegan diets. A plant-based diet focuses on incorporating more plant foods while still allowing for occasional consumption of animal products. In contrast, a vegan diet adheres to veganism, a belief system and practice that excludes all animal products.
The Link Between Vegetarian Diets and Fatigue
One of the most common complaints among those following plant-based, vegetarian, and vegan diets is persistent tiredness and fatigue. This often stems from nutrient deficiencies that arise when significant food groups are eliminated from the diet.
Identifying Potential Nutrient Deficiencies
If you experience fatigue while following a primarily plant-based diet, it's essential to consult a doctor and get your bloodwork tested. Key biochemical markers to check include:
- Iron (ferritin): Ferritin is the biomarker used to measure iron stores in the body.
- Vitamin B12: Vitamin B12 is crucial for energy production and nerve function.
- Complete Blood Count: This includes red blood cells, white blood cells, hematocrit, hemoglobin, and platelets, providing a comprehensive overview of blood health.
Common Causes of Fatigue in Vegetarian Diets
An RD shares 10 reasons you’re tired on a plant-based diet and simple ways to fix each issue, including the best plant-based foods for energy.
Read also: Is a Vegetarian Elimination Diet Right for You?
Insufficient Calorie Intake: Many people transition to a plant-based diet with the goal of weight loss. However, inadequate calorie consumption for your activity level can lead to low energy levels. Ensure you're consuming enough calories to support your basal metabolic rate (BMR) and exercise routine.
Vitamin B12 Deficiency: Vitamin B12 is essential for converting glucose to energy. Since plants cannot produce Vitamin B12, vegans often struggle to meet the recommended daily intake of 2.4 mcg. Incorporate plant-based Vitamin B12 foods or consider supplementation.
Iron Deficiency: Iron plays a vital role in transporting oxygen throughout the body. Heme iron, found in animal foods, is more easily absorbed than non-heme iron from plant-based sources. Consume iron-rich plant foods and pair them with vitamin C to enhance absorption.
Imbalance of Macronutrients: While carbohydrates are important for energy, some plant-based eaters overdo it on carbs and don’t have enough protein and fat in their diet.
Lack of Sleep: Low energy isn’t always from the diet. If you’re getting up early to workout and going to bed late, you’re probably not sleeping enough. Make a log of your sleep and wake times for a few days.
Read also: Healthy Vegetarian Eating
Inadequate Post-Workout Nutrition: After a workout, the body suppresses ghrelin, a hormone that stimulates hunger. However, your body needs calories and nutrients to restore energy levels. Replenish glycogen stores by consuming carbohydrates and protein after exercise.
Insufficient Fuel Before Workouts: If you notice that the fatigue starts to set in during your workout and lasts throughout the day, chances are you’re not eating enough to fuel your activity. If you haven’t eaten in a few hours, you’re likely starting your workout with your fuel tank on empty.
Poor Food Choices: It’s true that eating plant-based foods are great for your overall nutrition and health, but the types of plant-based foods you choose matter. Eating whole foods helps ensure that you get plenty of the aforementioned nutrients, like iron, and Vitamin B12, to keep energy levels high.
Overtraining: The term “overexercising” is relative and hard to pinpoint. Since everyone exercises different amounts, an excessive amount of activity can be different for everyone. When you overxercise, you may feel constantly tired and experience extreme muscle soreness and heavy legs.
Underlying Medical Conditions: It’s possible that you may be fatigued due to a medical condition, like an under active thyroid, a nutrient deficiency, Diabetes or another issue. Hopefully this isn’t the case, but you can’t rule it out. Ask them to do a full blood workup to find the underlying cause.
Read also: Is a Chicken-Inclusive Vegetarian Diet Right for You?
Common Mistakes on a Vegetarian Diet
A balanced vegetarian or vegan diet can provide many health benefits. These diets have been associated with weight loss, better blood sugar control, a decreased risk of heart disease and a lower risk of certain types of cancer (1, 2, 3, 4). However, it can be challenging to maintain a well-rounded vegetarian diet that provides all the nutrients you need.
Assuming Vegan Products Are Healthier: Just because a food product is labeled “vegetarian” or “vegan” doesn’t necessarily mean it’s healthier than the regular alternative. Many foods marketed as vegetarian or vegan are often highly processed, high in added sugar or lacking in nutrients. If you include these products in your diet, eat them only in moderation.
Not Getting Enough Vitamin B12: Vitamin B12 plays several important roles in the body. It’s important in the creation of red blood cells and DNA, among other processes (8). Vegetarians and vegans are at a greater risk of vitamin B12 deficiency, so make sure you consume fortified foods or B12 supplements.
Replacing Meat With Cheese: Instead of just replacing meat with cheese, make sure to also include a diverse range of plant foods in your diet to provide important nutrients.
Eating Too Few Calories: Vegans and vegetarians tend to have a lower calorie intake than people who eat meat and plants. If you’re following either of these diets, make sure you’re meeting your calorie needs.
Not Drinking Enough Water: Vegans and vegetarians usually eat a lot of fiber. Drinking enough water can help prevent digestive problems associated with increased fiber intake, such as gas, bloating and constipation.
Forgetting About Iron: Plant foods contain non-heme iron, which the body can’t absorb as well as the heme iron found in meat. Vegetarians should include iron-rich foods in the diet and pair them with vitamin C to increase absorption.
Not Eating Enough Whole Foods: Vegetarian diets should be rich in whole foods, such as fruits, vegetables and whole grains. They’ll help you maximize nutrient intake and promote a balanced diet.
Consuming a Diet Low in Calcium: Those who don’t consume milk or dairy products should consume other calcium-rich foods to meet their calcium needs.
Underestimating the Importance of Meal Planning: Planning meals ahead of time and knowing what your options are when dining out can ensure you maintain a diverse and balanced diet.
Not Eating Enough Protein-Rich Foods: Vegetarians should be mindful of protein intake and include one or two servings of high-protein plant foods with each meal.
Not Getting Enough Omega-3 Fatty Acids: Plant foods contain ALA, a type of omega-3 fatty acid that your body can only use in small amounts. Vegetarians should consume a good amount of ALA-rich foods, or use a plant-based supplement.
Eating Too Many Refined Carbs: Many vegetarians fall into the trap of replacing meat with refined carbs.
Addressing Iron Deficiency
Iron deficiency is a widespread issue, affecting both omnivores and vegetarians/vegans, with the latter at a higher risk. Non-heme iron, found in plant sources like dark leafy greens, nuts, legumes, tofu, and fortified cereals, is not as easily absorbed as heme iron from animal products.
Enhancing Iron Absorption
To increase the absorption of non-heme iron, consume foods rich in vitamin C (ascorbic acid) alongside iron-rich foods. For example, instead of coffee or tea (which can decrease iron absorption), pair your morning oatmeal with ½ cup (120 mL) of 100% orange juice mixed with water. The vitamin C in orange juice will enhance iron absorption from the oats.
Incorporating Iron-Rich Foods
Include a variety of plant-based iron sources in your diet. A vegan salad with marinated tofu, red peppers, and avocados on top of spinach can provide both protein and iron. Red peppers are an excellent source of vitamin C, further boosting iron absorption.
The Importance of Vitamin C
If you are eating more plant-based meals or are vegetarian/vegan, consider the role of important nutrients such as vitamin C and non-heme iron for adequate intake.
Vitamin C and Iron Absorption
Consuming foods with vitamin C (ascorbic acid) is how you increase absorption of non-heme iron. Instead of coffee or tea in the morning (both have shown to decrease iron absorption 6, 7) try ½ cup (120 mL) of 100% orange juice mixed with water to go with your oatmeal power bowl in the morning. The vitamin C from the orange juice will help to increase the absorption of iron from the oats.
Supplementation
If you are vegan/vegetarian or thinking of largely decreasing your animal protein consumption, there are supplements designed especially for you.
The global shift towards vegan and vegetarian diets
The global adoption of vegan and vegetarian diets has grown exponentially, largely influenced by ethical concerns regarding animal welfare, environmental sustainability, and perceived health benefits. Interest in vegan and vegetarian diets has grown globally. The campaign Veganuary saw over 700,000 participants in 2022. Germany led Google searches on veganism in 2023, followed by Austria and the UK. Global retail sales of plant-based meat products reached USD 6.1 billion in 2022. A 2021 survey found 81% of consumers tried plant-based milk, 48% tried other dairy alternatives, 44% tried vegan meat, and 25% tried a vegan egg substitute. Searches for “vegan food near me” spiked over 5000% in 2021, and the vegan leather market is projected to reach nearly USD 90 billion by 2025 [1]. By regions, in India, estimates suggest that 20-40% of the population follows a vegetarian diet, with veganism slowly growing in urban centers. In contrast, the United Kingdom reports around 5-7% vegetarians and 2% vegans, while in the United States, approximately 5% of adults are vegetarian and 3% identify as vegan.
The impact of these diets on neurological health
Despite the potential benefits of vegan and vegetarian diets, their impact on neurological health is a growing area of concern due to the reliance of the nervous system on specific nutrients that are either limited or less bioavailable in vegan and vegetarian diets. For instance, vitamin B12, which is predominantly found in animal-derived products, plays a crucial role in myelin synthesis and neurotransmitter production, and its deficiency is linked to neurodegenerative diseases, cognitive decline, and neuropathy [4]. Similarly, omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are vital for maintaining neuronal membrane fluidity and synaptic plasticity; yet, these fatty acids are scarce in vegan diets, with plant-based sources providing only alpha-linolenic acid (ALA), which has low conversion rates to EPA and DHA [5]. Iron and zinc, essential for neurotransmitter function and immune responses, are also less bioavailable in vegan and vegetarian diets due to the presence of phytates and polyphenols, which inhibit mineral absorption [6]. The potential risks associated with vegan and vegetarian diets are further com-pounded by the presence of antinutritional factors in plant-based foods. These compounds, which include phytates, lectins, oxalates, and tannins, are naturally occurring chemical defenses in plants designed to deter herbivory, but can interfere with human nutrient absorption and metabolism. Phytates, for instance, bind minerals like iron, zinc, and calcium, forming insoluble complexes that reduce their bioavailability [6]. Lectins, found in legumes and grains, can impair gastrointestinal function and lead to systemic inflammation when consumed in excess or not properly neutralized through cooking [7]. Oxalates, abundant in foods like spinach and rhubarb, have been associated with the formation of kidney stones and potential neurotoxic effects through calcium chelation [8]. While cooking and food preparation techniques, such as soaking, fermenting, and sprouting, can mitigate these effects, the potential cumulative impact of antinutritional factors on neurological health remains underexplored.
The effects of vegan and vegetarian diets on neurological health are also mediated by their impact on inflammation and oxidative stress.
Vegan and vegetarian diets are generally associated with lower levels of systemic inflammation due to their high content of antioxidants and anti-inflammatory phytonutrients, such as flavonoids, carotenoids, and polyphenols [9]. These compounds scavenge free radicals, reduce oxidative stress to cellular structures, and modulate inflammatory pathways, potentially offering neuroprotective effects [10]. However, the low intake of critical anti-inflammatory nutrients like omega-3 fatty acids, especially EPA and DHA, in vegan diets can offset these benefits, as these fatty acids play a pivotal role in regulating neuroinflammation and protecting neuronal integrity [11]. Furthermore, deficiencies in vitamin B12 and iron, common in vegan and vegetarian diets, have been linked to elevated homocysteine levels, a known risk factor for oxidative stress and neurodegenerative diseases [12]. These conflicting factors highlight the complexity of the relationship between vegan and vegetarian diets and neurological health, suggesting that, while these diets may offer protective benefits against inflammation and oxidative stress, they may also introduce vulnerabilities if not adequately balanced through supplementation and strategic dietary planning.
The Role of Antinutrients
In addition to the widely studied nutritional aspects, the role of antinutrients in neurological health warrants greater attention. Antinutrients, present in many plant-based foods, can influence the bioavailability of critical nutrients and disrupt metabolic pathways related to neurological function, such as inflammation and oxidative stress.
Nutritional Composition
It is essential to distinguish and compare the nutritional composition of vegan and vegetarian diets [13]. Vegan diets exclude all animal-derived products, which results in nutritional profiles characterized by lower intakes of vitamin B12, vitamin D, omega-3 fatty acids, iron, calcium, and iodine compared to both vegetarian and omnivorous diets. In contrast, vegetarian diets, which may include dairy and eggs, partially mitigate these deficiencies while still offering higher intakes of dietary fiber, magnesium, and antioxidants relative to omnivorous diets. Emerging research reveals a multifaceted interplay between these diets, gut health, inflammation, and cognitive outcomes, underscoring their potential to influence mental and neurological well-being positively or negatively depending on their composition and quality.
The Gut-Brain Axis
One of the most compelling aspects of vegan and vegetarian diets is their impact on the gut-brain axis, a bidirectional communication system linking the central nervous system and the gut microbiome. High dietary fiber intake, a hallmark of vegan and vegetarian diets, supports the proliferation of beneficial gut bacteria such as Bifidobacteria and Lactobacillus. These bacteria produce short-chain fatty acids (SCFAs) like butyrate, which play a critical role in maintaining the integrity of the blood-brain barrier and reducing neuroinflammation [14].
Systemic Anti-Inflammatory Effects
Beyond the gut microbiome, the systemic anti-inflammatory effects of vegan and vegetarian diets further contribute to their neurological benefits. Chronic low-grade inflammation is a well-established driver of neurodegenerative diseases, including Alzheimer’s and Parkinson’s, as well as mood disorders like depression. A meta-analysis by Tansey et al. (2022) demonstrated that individuals adhering to vegan and vegetarian diets consistently show lower levels of pro-inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) [16]. This reduction in systemic inflammation is likely attributable to the high intake of antioxidant-rich foods, such as fruits, vegetables, and whole grains, which counteract oxidative stress and mitigate the effects.
Practical Tips for Avoiding Fatigue on a Plant-Based Diet
Prioritize Whole Foods: Focus on consuming a variety of whole, unprocessed plant foods, including fruits, vegetables, whole grains, legumes, nuts, and seeds.
Ensure Adequate Calorie Intake: Track your calorie intake to ensure you're meeting your daily energy needs, especially if you're physically active.
Supplement Wisely: Consider supplementing with vitamin B12, vitamin D, and omega-3 fatty acids, as these nutrients are often lacking in vegan diets.
Optimize Iron Absorption: Pair iron-rich foods with vitamin C to enhance absorption.
Plan Your Meals: Plan your meals in advance to ensure you're getting a balanced intake of all essential nutrients.
Get Enough Sleep: Prioritize sleep to support overall energy levels and well-being.
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