If you struggle with sleepiness during the day, you're certainly not alone. According to the Centers for Disease Control and Prevention (CDC), more than 10 to 15 percent of U.S. adults often feel either very tired or exhausted.
It's little wonder, then, that energy drink consumption is on the rise. According to a June 2019 study in the American Journal of Preventive Medicine, more and more adolescents, young adults and middle-aged adults are drinking these beverages on a regular basis.
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The problem? Along with a temporary energy boost, these drinks come with several potential drawbacks, including increasing your risk for obesity and cardiovascular issues.
If you often find yourself reaching for a sugary, caffeinated fix, you may want to take a good look at the nutrients you're taking in — or not taking in. B-complex vitamins, vitamin D and the mineral iron have all proven effective in helping to stave off fatigue and promote healthy energy levels, so it's a good idea to make sure you're getting the recommended daily amounts.
Whether you get these nutrients through food or supplements, here's a look at the role each plays in the body, and how to tell if you should seek out a supplement.
A Note on Language
Here at LIVESTRONG.com, we try to use inclusive language when it comes to sex and gender. Some vitamin and dietary guidelines distinguish between nutritional needs for women and men, but nutrient requirements are usually more accurate when tailored to a person's individual calorie needs, activity level and overall health.
Still, we understand many people look up this information in relation to their own sex and gender, so we have used the words "women" and "men" throughout this article.
Get B-Complex for a Boost
What They Do: B-complex vitamins refers to a group of eight different nutrients: B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate or folic acid) and B12 (cobalamin), per the National Library of Medicine (NLM).
These essential vitamins assist the body in converting food into fuel. In addition, the B group helps form red blood cells, which are used to deliver oxygen throughout the body, per the NLM.
While each B vitamin has its own function — for example, the body needs vitamin B1 to produce adenosine triphosphate (ATP), a substance required by every cell in the body for energy — they often work together in the body, so it's best to get all of them in the proper amounts to ensure they're most effective, per Mount Sinai.
How Much You Need: According to the National Institutes of Health (NIH)'s Office of Dietary Supplements, the following daily amounts of B vitamins — in milligrams (mg) or micrograms (mcg) — are recommended:
- B1: 1.2 mg for males; 1.1 mg for females
- B2: 1.3 mg for males; 1.1 mg for females
- B3: 16 mg for males; 14 mg for females
- B5: 5 mg for all adults
- B6: 1.3 mg for males; 1.5 mg for females
- B7: 30 mcg for all adults
- B9: 400 mcg for all adults
- B12: 2.4 mcg for all adults
Tip
People who are pregnant or are chest/breastfeeding have different daily nutritional requirements and should speak with a doctor about how much vitamin B is right for them.
Where to Get Them: According to MyFoodData.com, which gathers information from the USDA's database, the foods highest in vitamin B include fish and shellfish, meats, poultry, nuts and fortified products, such as breakfast cereals and certain milks. Biotin (B7) and riboflavin (B2) are both found in eggs, while leafy greens such as spinach and collard greens are wise picks for folate (B9). B12, however, is not found in plants — it must be obtained from animal products, like meat, eggs, poultry, dairy, fish and shellfish.
Who Should Supplement: The NIH's Office of Dietary Supplements notes that B12 especially can help increase energy and improve endurance. And a deficiency in this nutrient is characterized by fatigue and weakness.
Unfortunately, between 5 and 15 percent of adults are deficient in vitamin B12, per the Mayo Clinic. Those who may be at a higher risk for deficiency include older adults, people with celiac disease or Crohn's disease or those who take certain medications, including the diabetes drug metformin and some drugs used to treat reflux or other gastrointestinal problems. If you think you might be deficient, talk to your doctor about which supplements might work best for you.
According to the Academy of Nutrition and Dietetics, vegans and vegetarians who don't eat meat, eggs or much dairy may also want to consider taking a B-complex supplement, although they can find B12 in nutritional yeast, fortified soy milk and soy-based meats, breakfast cereals and some fortified granola bars.
Add a Dose of D
What It Does: You may know that vitamin D helps your body absorb calcium and plays a critical role in maintaining healthy bones. But, according to the Mayo Clinic, it also helps keep your muscles, nerves and immune system in tip-top shape. And there's a growing body of research that suggests the nutrient is tied to how energetic we feel. An August 2014 study in the North American Journal of Medical Sciences, for example, found that adults who had fatigue and were deficient in vitamin D reported higher energy levels after being treated with the nutrient for five weeks. A similar December 2016 study in Medicine found a similar effect after four weeks.
How Much You Need: Adults younger than 70 should aim for 600 IU of vitamin D daily, per the Mayo Clinic, while those older than 70 should aim for 800 IU. Keep in mind, though, that between 1,000 and 2,000 IU is considered safe.
Where to Get It: Your body naturally produces vitamin D when it's exposed to sunlight. There are also a few foods high in vitamin D, according to MyFoodData.com, including fatty fish like tuna, salmon, herring, mackerel and sardines, as well as fish liver oils and egg yolks. For some people, however, fortified foods like some breakfast cereals, milk, yogurt, tofu and orange juice are better options.
Who Should Supplement: According to a June 2018 paper in Cureus, about 40 percent of the population is vitamin D-deficient. Because there are limited ways to get this nutrient through food sources, the Mayo Clinic suggests that adults who are deficient might benefit from taking a supplement.
Warning
Taking too much vitamin D can be a problem as it may damage the kidneys and heart valves, per the University of Rochester Medical Center. It may also interact negatively if you take antacids, digoxin or digitoxin. If you take these medications or have had heart or kidney issues in the past, speak to your doctor before taking a D supplement.
Pump Some (Dietary) Iron
What It Does: The mineral iron is an essential part of hemoglobin, the substance in the blood that carries oxygen to the rest of the body. It's also a component of myoglobin, a protein that sends oxygen into the muscles, per the NIH's Office of Dietary Supplements. Iron is necessary for growth and development, especially in kids and adolescents, according to the Mayo Clinic.
Your body stores the iron it doesn't use, but if these stores dip too low, not enough red blood cells can be made to carry oxygen efficiently. In this case, according to the Academy of Nutrition and Dietetics, you would develop a condition called iron deficiency anemia, which is marked by fatigue and weakness.
How Much You Need: According to the Institute of Medicine of the National Academies, adult women older than 51 and all adult men need 8 milligrams of iron daily, while women ages 19 to 50 require 18 milligrams per day. Note that women who are pregnant or breastfeeding have different nutritional needs.
Tip
Pair foods rich in non-heme iron with those high in vitamin C, which helps your body absorb the mineral, according to the Mayo Clinic.
Where to Get It: There are two types of dietary iron: heme and non-heme. Heme iron is easily absorbed by the body and the best source of iron for people who are lacking in this mineral, according to the Iron Disorders Institute. Heme iron is found in meat, with red meat being an especially good source.
Non-heme iron must be changed by the body before it can be absorbed, so it is a slightly less efficient source of the mineral. However, non-heme iron accounts for the majority of iron we eat, according to the Academy of Nutrition and Dietetics. It can be found in meats as well as grains such as rice, oats and wheat, and in fortified foods. Other sources include lentils, spinach and white beans.
Who Should Supplement: Most people in the U.S. get adequate amounts of iron through their diet, according to the Mayo Clinic, but adults who may be at risk for iron deficiency include people who are pregnant, those with abnormally heavy menstrual bleeding, frequent blood donors and those who have gastrointestinal disorders such as celiac disease or inflammatory bowel disease.
If you believe you may have an iron deficiency, talk to your doctor or health care provider about whether an iron supplement may be the right move for you.
Warning
Excessive iron supplementation can cause stomach pain, nausea and vomiting. Be especially careful if you're taking medications for Parkinson's, restless leg syndrome or hypothyroidism, as too much iron can reduce their efficacy, according to the Mayo Clinic.
- National Institutes of Heath, Office of Dietary Supplements: "B12"
- National Library of Medicine: "B Vitamins"
- Academy of Nutrition and Dietetics: Food Sources of 5 Important Nutrients for Vegetarians
- National Institutes of Heath, Office of Dietary Supplements: Iron
- Mayo Clinic: Iron deficiency in children: Prevention tips for parents
- Mayo Clinic: Mayo Clinic Q and A: How much vitamin D do I need?
- University of Rochester Medical Center: Vitamin D
- Centers for Disease Control and Prevention: "QuickStats: Percentage of Adults Who Often Felt Very Tired or Exhausted in the Past 3 Months,* by Sex and Age Group - National Health Interview Survey, United States, 2010-2011"
- American Journal of Preventive Medicine: "Trends in Energy Drink Consumption Among U.S. Adolescents and Adults, 2003–2016"
- Mayo Clinic: "Vitamin B-12 Supplements Recommended for Older Adults"
- MyFoodData.com: "200 Foods Highest in Vitamin D"
- Cureus: "Prevalence of Vitamin D Deficiency and Associated Risk Factors in the US Population (2011-2012)"
- North American Journal of Medical Sciences: "Correction of Low Vitamin D Improves Fatigue: Effect of Correction of Low Vitamin D in Fatigue Study (EViDiF Study)"
- Medicine: "Effect of vitamin D3 on self-perceived fatigue"
- Academy of Nutrition and Dietetics: "Iron"
- Iron Disorders Institute: "Iron We Consume"
- Institute of Medicine of the National Academies: "Dietary Reference Intakes (DRIs): Elements"
- Mount Sinai: "Vitamin B1 (Thiamine)"
- MyFoodData: "Food Lists"