(BPT) – Key nutrients are cornerstones of good health, yet deficiency among Americans is skyrocketing. Are you unknowingly suffering from a nutrient shortage?

Dr. Ronald Hoffman, medical director of the Hoffman Center in New York City and host of the radio program “Intelligent Medicine,” points to three major vitamin deficiencies affecting people today. He offers his expert insight on each and what you can do to fix the problem.

Omega-3s

“Many North Americans are omega-3 deficient because we eat highly processed foods that lack essential fatty acids and not enough oily fish,” says Hoffman. “The problem is particularly acute for vegetarians, those who prefer not to eat fish or are allergic, and young people who are picky eaters.”

In the U.S. up to 91 percent of Americans are omega-3 deficient and a Harvard study ranked omega-3 deficiency as the eighth leading cause of preventable death. Omega-3s are considered “essential” because the body cannot make them and must ingest them from external sources.

Omega-3s benefit the body in countless ways, including the optimal functioning of cell membranes. “The cell membrane is responsible for translating messages from adjacent cells and organs into chemical work inside the cell,” Hoffman explains.

There are more than 27,000 published studies on omega-3s showing the benefit of omega-3s, from brain and heart health to boosting mood and skin health. Omega-3s are particularly notable for cardiovascular health. The American Heart Association recommends at least 1 gram of omega-3 EPA and DHA a day for those with established coronary artery disease.

“Fish like salmon, tuna, mackerel and sardines provide the most omega-3s,” says Hoffman. “I also recommend supplements in soft gels or liquid form, or gummies and emulsions for kids.”

He notes when selecting a supplement, freshness and dosage is crucial.

Vitamin D

Because people can produce natural vitamin D3 (cholecalciferol) with sunlight, many assume they get enough. In reality, vitamin D deficiency is widespread. Up to 36 percent of Americans are vitamin D deficient and up to 91 percent of pregnant women in the U.S. aren’t getting enough of the sunshine vitamin.

“Vitamin D is actually more than a vitamin,” Hoffman explains. “It’s a ‘pro-hormone’ and modifies the expression of many genes. This means it plays a powerful role, not just in building bone, but in the body’s immunity, muscle strength and even mood and cognition.”

Many factors affect a person’s ability to make enough vitamin D, including age and location. During sunny seasons, 10 to 45 minutes of direct sun exposure daily can help maintain adequate vitamin D, but for many people this is not possible all year long and supplementation is necessary.

“Current recommendations for vitamin D are 600 IU for ages 1-70; for pregnant or breast-feeding women and individuals over 70 it’s 800 IU. But this dosage could short-change many individuals with special needs or who have inadequate sun exposure,” says Hoffman. “The best bet is to measure vitamin D in the blood and supplement until an optimal blood level of 40-60 nanograms per milliliter is achieved.”

Magnesium

Most people have heard of magnesium but are unsure how it impacts their health. An estimated 50 to 80 percent of Americans are deficient in magnesium, mostly due to a diet of refined foods.

“Magnesium is an essential mineral that is a co-factor for literally hundreds of biochemical pathways in the body,” Hoffman explains. “It is particularly crucial for energy production in the mitochondria, tiny powerhouses within the cells. Therefore, inadequate magnesium can be responsible for physical fatigue and mental depression.”

He also notes magnesium, along with calcium and vitamin D, is essential for bone health.

You can correct a deficiency by eating a diet rich in plant-based, unprocessed foods like nuts, leafy greens, avocados and dried fruit. However, many people require supplements to reach optimal magnesium levels.

“Check labels for the amount of elemental magnesium in each supplement and shoot for 200-500 mg daily. Be sure to meet with your doctor prior to taking any supplement,” says Hoffman.