Constantly Tired? Here's Why Millions of Americans Are Struggling and What Might Be Behind It

Fatigue Doesn’t Have to Be Normal—Learn What’s Depleting Your Energy

Fatigue is one of the most common complaints in the United States. A 2022 national survey revealed that 13.5 percent of American adults report feeling “very tired” or “exhausted” most days or every day over a three-month period. That’s over 1 in 10 people! Among them, women aged 18 to 44 showed the highest rates of fatigue, with over 20 percent of them reporting this constant drain.

The reality of constant fatigue is not merely a result of overwork or the hectic pace of modern life. As a registered dietitian and nutritional neuroscientist, I’ve observed that these persistent tiredness levels are often deeply connected to lifestyle choices and dietary deficiencies. With years of research backing these observations, I’ve found that there are two key nutrients—vitamin D and vitamin B12—that are consistently linked to low energy levels. If you’re constantly feeling drained, these nutrients (or the lack of them) may hold the key to understanding your fatigue.

Moreover, there’s another factor that could be contributing to the exhaustion: omega-3 fatty acids. Together, these three nutrients play a crucial role in regulating your body’s energy systems. A deficiency in any of them can leave you feeling perpetually sluggish and mentally fatigued. Let’s dive deeper into why these nutrients are so important, how to recognize deficiencies, and what you can do to fix the problem.

Vitamin D: The Sunshine Vitamin and Its Link to Fatigue

Over 40 percent of American adults are vitamin D deficient. This vitamin is crucial for many bodily functions, from immune system health to bone density. But what many don’t realize is that a lack of vitamin D is strongly correlated with feelings of fatigue. Individuals with low levels of vitamin D often report muscle weakness, bone pain, mood disorders, and cognitive decline—all symptoms that contribute to an overall sense of tiredness.

Vitamin D is primarily synthesized by the body when the skin is exposed to sunlight. However, many people struggle to get enough sunlight, especially during the winter months or if they live in areas with long periods of cloud cover. Other sources of vitamin D include foods such as fatty fish (e.g., salmon, sardines, mackerel), fortified dairy products, and egg yolks. For vegetarians and vegans, fortified plant-based milks and cereals are also excellent options. Mushrooms, especially those exposed to ultraviolet (UV) light, can also be a good source of vitamin D.

The recommended daily intake of vitamin D varies by age, with 600 IU suggested for adults aged 1 to 70 and 800 IU for individuals over 70. To put it into perspective, just over 5 ounces (150 grams) of sockeye salmon provides about 800 IU of vitamin D. For people who are deficient, your doctor may recommend higher doses to elevate blood levels to normal.

Vitamin B12: The Energy Powerhouse

Around 20 percent of Americans have inadequate vitamin B12 levels. This vitamin plays a critical role in energy production and is essential for red blood cell formation, nervous system function, and DNA synthesis. Low levels of vitamin B12 can lead to fatigue, weakness, and even anemia. These symptoms alone can be debilitating and lead to a feeling of constant exhaustion.

B12 is primarily found in animal products such as meat, fish, dairy, and eggs. This makes it especially difficult for vegetarians and vegans to meet their daily B12 requirements. Vegetarians and vegans who don’t supplement with B12 may be at risk of a deficiency, which can impact their energy levels and overall well-being.

For those who don’t consume animal products, B12 supplementation is often necessary. The recommended daily amount for anyone over 4 years old is 2.4 micrograms—roughly equivalent to the amount in 3 ounces of tuna or Atlantic salmon. Pregnant and breastfeeding women may require slightly more.

While B12 supplements can be highly effective in addressing deficiencies, they should not be considered a replacement for whole foods. It’s important to remember that whole foods contain a synergy of nutrients that work better in the body than isolated supplements. Moreover, supplements are less strictly regulated by the FDA, so their potency can be inconsistent. Real food, with its rich nutrient profile, remains the best source.

Omega-3 Fatty Acids: The Essential Nutrient for brain health

Another nutrient essential for combating fatigue is omega-3 fatty acids. It’s estimated that up to 87 percent of adults aged 40 to 59, and 80 percent of individuals over 60, fail to meet the daily recommendations for omega-3s. Even more concerning, many pregnant women don’t get enough of these vital fats, which are crucial for both brain and cardiovascular health.

Omega-3 fatty acids play an essential role in regulating brain function, and a deficiency in these fats is often linked to higher anxiety, depression, and impaired cognitive function. When cognitive function is compromised, fatigue is often a direct result. These deficiencies don’t just contribute to mental exhaustion but can also hinder energy production at a cellular level.

The best sources of omega-3 fatty acids are fatty fish such as salmon, mackerel, and sardines. For vegetarians and vegans, flaxseeds, chia seeds, and walnuts provide a plant-based alternative. However, it’s worth noting that the omega-3s in fish are absorbed by the body more efficiently than those in plant sources. In addition, whole flaxseed has a tough outer shell, which makes it harder for the body to digest. Opt for ground flaxseed for better absorption.

The Impact of Alcohol on Fatigue

While alcohol might seem like an easy way to unwind after a long day, it actually contributes to fatigue. When alcohol is consumed, the body treats it as a toxin and prioritizes metabolizing it over other nutrients. This leads to a reduction in the use of carbohydrates and fat for energy. Consequently, energy production is compromised, and you may feel more tired.

Alcohol also reduces the body’s ability to absorb B vitamins, which are crucial for energy production. So, while alcohol may temporarily relax you, it ultimately leaves you feeling exhausted and lethargic the next day.

Lifestyle Factors Contributing to Fatigue

Diet isn’t the only factor contributing to fatigue. A combination of sunlight, exercise, quality sleep, and stress management is essential for reducing tiredness and improving energy levels.

Sunlight is one of the primary ways the body produces vitamin D, and just a few minutes to half an hour of exposure can make a difference. How much sunlight you need varies depending on location, season, and skin type, but exposing your skin to direct sunlight is the most effective way to boost your vitamin D levels.

Exercise for Energy

While it may sound counterintuitive, the more you exercise, the more energy you’ll have. Exercise boosts blood flow, improves oxygen delivery, and helps release endorphins—hormones that reduce pain and stress while elevating mood. Exercise helps the body become more efficient at producing energy. In contrast, sedentary lifestyles lead to a drop in energy levels and more feelings of lethargy.

Aim for at least 150 minutes of moderate exercise each week. This can include activities like brisk walking, cycling, swimming, and strength training.

The Importance of Sleep

Perhaps the most important factor in combatting fatigue is quality sleep. Getting seven to nine hours of rest each night allows your body to recover and regenerate. Poor sleep disrupts natural recovery processes and leaves you feeling exhausted.

To improve your sleep, develop a calming bedtime routine, limit screen time, and avoid blue light exposure from phones and computers at least 30 to 60 minutes before bed. Engaging in relaxing activities such as reading, meditation, or gentle stretching before bed can help signal your body that it’s time to rest.

Conclusion: Taking Control of Your Fatigue

Fatigue doesn’t have to be a permanent state. By addressing nutritional deficiencies, avoiding alcohol (or at least moderating consumption), and making healthier lifestyle choices, you can combat fatigue and reclaim your energy. Focus on getting enough of the essential nutrients—vitamin D, B12, and omega-3 fatty acids—and engage in daily habits that improve sunlight exposure, exercise, and sleep.

Small, consistent changes can make all the difference in how you feel. If you’re feeling drained, it’s time to take charge of your energy levels by improving your diet and lifestyle.