Consider this question the next time you feel low on energy: how are you eating? Here are some of the most common diet-related reasons that play a major role in your energy levels.


If you are feeling tired, achy, and anxious most days, you probably just blame it on a stressful schedule, getting older, or shrug it off since you are used to feeling that way. However, if these symptoms are paired with other health issues like lack of focus, depression, mood swings, or loss of appetite, you may actually be dealing with a nutrient deficiency.

Here are 5 of the most common nutrient deficiencies that may be contributing to your lack of energy:


Iron is an important mineral needed by the body to help deliver oxygen to drive energy production in our cells. A good source for iron can be found in lean meats, seafood, poultry, beans, nuts, and spinach.  Plant-based iron is best absorbed by the body when eaten with iron-rich animal proteins or vitamin C rich foods, such as citrus fruits, strawberries, sweet peppers, tomatoes, and broccoli.

Iron deficiency, also known as anemia, can cause:

  • Extreme fatigue and lack of energy
  • Poor memory and concentration
  • Weakened ability to fight off germs and infections
  • Trouble controlling body temperature
  • Heart palpitations and shortness of breath

While the average person requires at least 8 mg per day, infants, children, growing teens, pregnant or breastfeeding moms.  Those with certain GI disorders, cancer, or heart conditions, also require more.


Vitamin B12 is an essential water-soluble vitamin that is important for healthy nerve cells and cellular replication process. It is typically found in animal products such as beef, poultry, seafood, pork, and dairy products (such as milk, cheese, and yogurt).

Most people get enough vitamin B12 from diet alone, but those who are vegetarian, vegan, or have malabsorption issues may not get enough to stay within normal levels.  A healthy range is defined between 200 and 900 pg/ml.  Below this number, you may experience symptoms such as:

  • Fatigue
  • Weakness
  • Constipation
  • Loss of appetite and weight loss
  • Difficulty maintaining balance,
  • Depression
  • Cognitive decline, such as confusion, dementia, and poor memory.

However, high B12 levels above 900 pg/ml can also be cause for concern since it may mask a malabsorption issue.  These individuals may experience symptoms of vitamin B12 deficiency, but still report high levels.  In this case, it is important to get your vitamin B12 retested. If your level is still high, you may be tested for liver or malabsorption issues.


Also known as the “sunshine vitamin,” vitamin D is a fat-soluble vitamin that you can get from regular exposure to sunlight.  Just 10-15 minutes of sunlight exposure on your arms and legs can provide enough daily, or weekly vitamin D depending on the intensity of the sun.  

Vitamin D is typically consumed from dairy products such as milk and cheese, as well as egg yolks and fatty fish like salmon or tuna. If you are taking vitamin D supplements, it is best to take them with foods that contain a moderate amount of fat for best absorption.  

By working with magnesium and calcium, Vitamin D plans a vital role in bone health as well as immune health and hormonal balance. Those with darker skin, who live in northern climates where sunlight is weaker, or who do not spend a lot of time outdoors can be at risk for vitamin D deficiency. It may not present any noticeable symptoms, but some do experience:

  • Feeling tired
  • Aches and pains
  • Depression

Recent studies it has been found that those with low levels of vitamin D may have difficulty with weight loss as well as maintaining healthy blood glucose levels.  Those on steroid medication may also be at risk for a vitamin D deficiency since steroids can cause impaired vitamin D metabolism. Work with your doctor if you are taking medications such as Orlistat and certain cholesterol-lowering medications, which may interact with vitamin D supplements.  


Magnesium is a mineral found in green leafy vegetables, nuts, and seeds, as well as whole grain foods such as oats, barley, rice, wheat, and corn. Many people may not realize they are magnesium-deficient since symptoms can make you feel just ‘under the weather’ such as:

  • Feeling tired
  • Sleeping problems
  • Agitation
  • Anxiety
  • Irritability
  • Low blood pressure

Such symptoms have been found to become more apparent if someone starts a vitamin D supplement regimen without magnesium supplementation.  Because vitamin D and magnesium work together in the body, magnesium deficiency will also impact the way vitamin D is absorbed in the body.


In recent years, Omega-3 fatty acids have become mainstream because of its heart-healthy benefits.  Omega-3 fatty acids are typically consumed through fatty fish, soybeans, nuts, seeds, and spinach.  If you are low in Omega-3 fatty acids, you may experience symptoms such as:

  • Feeling tired
  • Rough, dry skin
  • Brittle hair and nails
  • Sleeping issues
  • Depression
  • Anxiety
  • Problems with concentration and memory

Studies have shown that proper intake, around 500 milligrams of EPA and DHA, can help lower blood pressure and may be protective against Alzheimer’s disease and dementia. This can be done by taking a fish oil supplement that contains the proper amount of EPA and DHA or by eating two servings, about 3-4 ounces each, of fatty fish a week.

If you suspect you have a nutrient deficiency related to your energy levels, be your own advocate and get tested. Make a visit to your health care provider, and make sure they order the proper tests to find out the cause of your symptoms.

It’s time to get back on track in living your best life, inside and out.


Staci Gulbin, MS, MEd, RD, LDN is a Portland-based Registered Dietitian with a licensed private practice in Oregon and Maryland. Staci focuses on helping others be confident in the choices they make and to value themselves enough to make healthier decisions, even in moments where family and work life can be overwhelming.