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Get excited about nutrition, and learn as you go with these information-packed resources on a wide variety of nutrition-centric topics! Our bistroMD experts review the importance of the macronutrients protein, fat, and carbohydrates, as well as how to make them work most efficiently for you.

What Vitamins Do You Really Need?

The ideal situation is to obtain all of the nutrients that you need by consuming a healthy diet. But what if you are not sure about your vitamin intake – what vitamins do you really need?

What Vitamins Do You Really Need?

Vitamins can be expensive, laborious to take, and in some cases might be unnecessary. The ideal situation is to obtain all of the nutrients that you need by consuming a healthy diet. But what if you are not sure about your vitamin intake – what vitamins do you really need?

When you eat a strawberry, not only do you get the vitamin C it contains, but also the fiber, which can reduce cholesterol, and the potassium, which can help lower blood pressure.

If you do not eat strawberries, you would have to take a fiber supplement, a supplement containing vitamin C, and a potassium pill in order to get all the nutrition in a serving of strawberries. Beyond that, strawberries contain plant chemicals that are chemo protective – which means they reduce the risk of developing cancerous cells. So there just really isn't any supplement substitute for a strawberry.

Examining Big Data on Dietary Habits

If you are eating a 'normal diet' – or at least the diet that most American adults eat – then you probably follow the same trends that the National Health and Nutrition Examination Survey (NHANES) picks up. This survey has been continuing for many decades in the United States, and it assesses what people eat, and what their health status looks like.

In the document published in 2012 entitled "What we eat in America", researchers have identified key nutrients that most American's have probably not gotten enough of in adulthood. So these might be some nutrients and vitamins you might need.

NHANES reveals that the primary nutrients of concern – because we don't seem to get enough of them—for adults are fiber, choline, calcium, potassium. If we can bring our intake of fiber up – we can reduce cholesterol and risk of diabetes. If we bring our choline intake up – our liver will be protected from fatty liver complications. If we can increase our calcium intake, it can help us lose weight and build strong bones. If we increase potassium each day – we can lower our blood pressure if it is high. So you can see there are many reasons why making sure we are getting the vitamins we need is vastly important.

For adult females, an additional nutrient target that is difficult to meet is iron, with the average female taking in around 14mg/day with a requirement of 18mg/day for females of child-bearing age. It can be difficult to obtain enough iron from the diet, especially if you are trying to trim up calories to lose weight, so a supplement for iron might be a good idea.

For our beloved older adult population the primary nutrients of concern are related to reduced absorption of these nutrients from foods. The USDA has reported that calcium, vitamin D, and vitamin B12 intakes are low in older adults, and supplementing may not be a bad idea. Many older adults do not get enough of these particular nutrients in a standard diet, and in the case of vitamin D, not enough sunlight and reduced ability to convert cholesterol in the skin in order to produce vitamin D internally can cause a lower intake level.

Vitamins and Supplements and Weight Loss

When it comes to a weight loss diet, cutting calories or cutting out a particular food group, you are cutting out the nutrients that come with that food group. For example, if you begin a low-carb diet – many bread and cereal products are fortified with b-vitamins—such as folate, riboflavin, and vitamin b12, as well as iron. So you would begin missing out on your normal intake of those nutrients by removing that food group. Many gluten-free products are not re-fortified with vitamins and iron following processing – so going gluten free can put you at risk for certain vitamin and nutrient deficiencies for this reason, and you might need a vitamin supplement.

Another problem with reducing carbohydrate to very low intakes is the subsequent decrease in fiber that results. Fiber comes from whole grains, beans, peas, legumes, fruits, and vegetables. When you reduce your carbohydrate intake, it's difficult maintain your fiber intake. Consuming a fiber supplement might be a good idea in this situation, or you could try eating a Haas avocado (11g fiber) and lots of veggies and leafy greens every day.

If you choose to try a vegetarian diet, cutting protein means cutting back on vital amino acids, vitamin B12 from food sources, as well as highly absorbable iron, copper, selenium, and zinc. Minerals from plant foods are not as well absorbed as from animal foods, so you might consider supplementing with minerals if you switch to a vegetarian diet. And supplementing with vitamin B12 is a must if you begin following a vegan diet.

Something else to keep in mind when you are reducing your protein intake –your muscle is the largest contributor to basal metabolic rate – which is the number of calories you burn at rest. When you reduce your protein intake, most of the time you will lose some of your muscle tissue, as it gets turned over in order to help provide the amino acids your liver needs to create enzymes and build tissues. If you decrease fat on a diet, then you are at a risk for a lower intake of fat soluble vitamins, as well as an inadequate intake of heart healthy, anti-inflammatory omega - 3 fatty acids. Fat-soluble vitamins include vitamin D, vitamin E, vitamin A, and vitamin K – all very important for your long-term health.

Overall, what vitamins you really need depends upon how you are currently eating. If you want to find out , the USDA has created an easy, online tool that lets you assess your nutrient intake by entering the foods and beverages that you consumed on any given day and allowing you to analyze your intake. Just visit to try it out for yourself.


U.S. Department of Agriculture, Agricultural Research Service. 2014. Nutrient Intakes from Food and Beverages: Mean Amounts Consumed per Individual, by Gender and Age, What We Eat in America, NHANES 2011-2012.

Dietary Reference Intakes (DRIs): Tolerable Upper Intake Levels, Elements Food and Nutrition Board, Institute of Medicine, National Academies.

Written By Sarah Asay, RDN. Published on December 30, 2015. Updated on January 11, 2018.


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