Vitamin deficiency may be why you’re so tired – a nutritional neuroscientist explains how to jump-start your energy by getting key nutrients in a well-rounded diet, along with more sleep and exercise

Feeling drained and lethargic is common: A 2022 national survey found that 13.5% of US adults said they felt “very tired” or “exhausted” most days or every day for three months.

Women aged 18 to 44 had the highest rate of fatigue – just over 20%.

Being tired is connected to something deeper than overwork or a sign of the times. I am a registered dietitian and nutritional neuroscientist. My research, along with the work of others in the field, shows that your diet and lifestyle choices may be contributing to your struggles. These two factors are closely related and could be the key to understanding what is holding you back.

Specifically, insufficient intake of three essential nutrients – vitamin D, vitamin B12 and omega-3 fatty acids – is associated with low energy levels.

Vitamin D

More than 40% of American adults are vitamin D deficient. Low levels are associated with fatigue, bone pain, muscle weakness, mood disorders and cognitive decline.

Foods rich in vitamin D include fatty fish such as salmon, sardines, freshwater trout, fortified dairy products and egg yolks. Among the sources for vegetarians and vegans are fortified milks and cereals of plant origin and certain types of mushrooms.

The US government recommended daily amount of vitamin D it’s 400 international units, or IU, for infants up to 12 months old, 600 IU for people ages 1 to 70, and 800 IU for people over 70. Just over 5 ounces (150 grams) of salmon fillet has about 800 IU of vitamin D. If you are low in the vitamin, your doctor may prescribe a higher dose than the recommended daily amount to raise your blood levels to normal levels.

Vitamin B12

About 20% of Americans have it insufficient levels of vitamin B12which can impair energy production and lead to anemia, resulting in fatigue.

Low B12 levels are significantly higher in older people, pregnant and lactating womenpeople with gastrointestinal disorders such as inflammatory bowel diseasethose who take certain medications such as proton pump inhibitors and people with alcohol use disorder.

Because vitamin B12 is found primarily in meat, fish, dairy and eggs, vegetarians and vegans should consider taking a vitamin B12 supplement. The recommended daily amount for people age 4 and older is 2.4 micrograms, about what is found in 3 ounces of tuna or Atlantic salmon. Pregnant and lactating women they require a little more.

Taking B12 supplements can be just as effective as getting the vitamin from food – and taking the supplement with food may enhance its absorption.

That said, here’s a note about supplements in general: While they can be beneficial, they shouldn’t replace whole foods.

It’s not just supplements less strictly regulated by the Food and Drug Administration compared to prescription and over-the-counter drugsmaking their potency uncertain, but real food also provides a complex array of nutrients that work synergistically. Many supplements on the market feature large servings of vegetables, but nothing beats real food.

Omega-3 fatty acids

About 87% of adults aged 40 to 59 and about 80% of those aged 60 and over, don’t get enough omega-3 fatty acids meet dietary recommendations. Not many pregnant women either.

Omega-3 fatty acids are vital for brain health, and a deficiency can lead to higher levels of anxiety and depression and impaired cognitive function. Taken together, these deficiencies can increase fatigue.

The best sources of omega-3 fatty acids they are oily fishbut if you’re strictly vegan, flaxseeds, chia seeds, and walnuts can be great alternatives. However, it is worth noting that omega-3 in fish is better absorbed by the body rather than plant sources – and this determines how effectively the body can use omega-3s.

Also, whole flaxseed has a hard outer shell, which makes it more difficult to digest and absorb its nutrients. But ground flaxseed has been broken down, producing omega-3s and other nutrients more available for absorption.

The role of alcohol

Although alcohol can provide a sense of relaxation at this time, in fact contributes to fatigue after the buzzer goes off. Alcohol it is a toxin; it forces your body to prioritize its metabolism over that of nutrients, meaning the body reduces its use of carbohydrates and fat for energy.

Alcohol too reduces the absorption of B vitaminswhich consequently affects energy production. The bottom line: If you drink alcohol, you will eventually feel tired.

Lifestyle factors

Diet is not everything. Sunlightexercise, better sleep, and stress management are all critical factors in reducing fatigue.

Your body can produce vitamin D from sunlightand you don’t need much. A few minutes to half an hour of sun exposure can help most people get what they need. The time can vary depending on where you live, how much clothing you wear, and what time of year you have the exposure. You will reach your daily limit of vitamin D much faster on a sunny day during the summer than on a cloudy day in the winter.

And it may sound counterintuitive, but the more you exercise, the the more energy you will produce; exercise doesn’t tire you. Instead, it boosts energy, along with mood, by improving blood flow and helping to release endorphins, which are hormones produced by the body to relieve pain or stress.

Without exercise, the human body becomes less efficient at producing energy, which leads to lethargy. Combined with erratic blood sugar levels – often caused by diets high in refined sugars and low in nutrients – these energy dips and spikes can leave you feeling irritable and tired.

A goal at least 150 minutes of moderate exercise each week through activities such as brisk walking, cycling, swimming and strength training.

Bad sleep makes things even worse. Not getting enough rest disrupts the body’s natural recovery processes and will leave you with decreased energy and focus.

So you should try to get seven to nine hours of quality sleep every night. For some people this is not easy. Establishing a relaxing bedtime routine helps, and limiting screen time is key.

Avoid phones, computers, and other screens for at least 30 to 60 minutes before bed. The blue light emitted by screens can affect your body’s production of melatonina hormone that helps regulate sleep. Instead, activities like reading, meditating, or gentle stretching help signal your body that it’s time to sleep.

In short, there are things you can do about your fatigue. Smart choices help optimize mood, energy levels, and overall health, and reduce the sluggishness you feel during the day.

Make no mistake: your diet and lifestyle can make the difference between being alert or perishing.