Kat Barefield, MS, RD, CPT
One of the key functions of B vitamins is extracting energy
from food to either be used immediately by cells to fuel various metabolic
reactions or stored for later use. Because of this, some are concerned that consuming
extra B vitamins can lead to unwanted weight gain.
This article will answer that question and cover a bit more,
including:
- The key functions of B vitamins
- Why B vitamins are added to the food supply
- Which vitamins you may be lacking
- The evidence on whether consuming excess B vitamins leads to weight gain
- Keep reading to get the full scoop.
Chief Function of B Vitamins
The B vitamins include:
- Thiamine – B1
- Riboflavin – B2
- Niacin – B3
- Pantothenic acid – B5
- Pyridoxine – B6
- Biotin – B7
- Folate/folic acid – B9
- Cobalamin – B12
Choline is not a vitamin since the body produces
minimal amounts, but it is an essential
micronutrient similar to the B vitamins. Therefore, choline is included in this
group.
B vitamins are one of the six types of nutrients that are
essential for the proper functioning of the trillions of cells which make up
the human body. By definition, “essential nutrient” means it’s something
required to sustain life, but the body doesn’t make it so we must consume it on
a regular basis.
B vitamins are water
soluble and excess amounts are excreted in urine, sometimes resulting in a
harmless bright yellow color.
Some of their functions include:
- Converting protein, carbs and fat into energy
cells can use
- Breaking down glycogen and producing glucose
- Synthesizing other compounds such as cholesterol,
fatty acids and neurotransmitters which help regulate appetite
- DNA synthesis and replication
- Helping to maintain proper function of the
nervous system
- Producing and assisting antioxidants
Good Sources of B Vitamins
B vitamins can be found in many different foods as shown in
the table below.
Foods/Food
Group
|
B Vitamins
|
Fortified grains
– cereals, breads, pastas
|
B1, B2, B3, B5, B6, B7, Folic acid, B12
|
Legumes –
beans, peas and lentils
|
B1, B5,
Folate
|
Fruits and
vegetables
|
B1, B2, B3,
B5, B6, B7, Folate, Choline
|
Meat, fish,
poultry
|
B1, B2, B3,
B5, B7, B12, Folate
|
Organ meat
|
B2, B5, B6,
B7, Choline
|
Milk and milk
products
|
B1, B2, B3,
B5, B6, B7, B12
|
Eggs
|
B2, B5, B7,
B12, Choline, Folate
|
Nuts and
seeds
|
B1, B2, B3,
B5, B6, B7, Folate
|
Consuming a wide variety of foods from all the major food
groups helps prevent deficiency, which is a rare occurrence in most developed
countries. One reason for this is the addition of B vitamins to grain products
such as breads, cereals and pasta. In the early 1940’s, wheat flour was
enriched with thiamin, riboflavin, niacin and iron and infant formulas were fortified
with vitamins. In 1998, grains were fortified with folic acid in the United
States.
Vitamin Intakes in the US
Daily amounts of each of the B vitamins that you should aim
to consume are known as the Recommended Dietary Allowance (RDA). The
RDAs
are based on gender, age, and life stage such as pregnancy and lactation. Most
Americans consume enough of most of the B vitamins, but still fall short of
others.
Although vitamin deficiencies are rare, data from over
15,000 Americans at least 9 years of age shows that nearly one third of the
U.S. population is at risk of deficiency for at least one vitamin and anemia
(lack of iron).
[1]
Higher risks of deficiency were observed in certain people:
- Women
- Blacks
- Low-income households
- Underweight
- Obese
The highest risk of deficiency was
among non-users of dietary supplements compared to those who used a
full-spectrum multivitamin and mineral and other dietary supplements.
Although not deficient, even more individuals fall significantly
short of daily recommended amounts of several vitamins and minerals, as
highlighted by the 2020 Dietary Guidelines for Americans Report, written by a
committee of 20 nutrient scientists, physicians and dietitians
from various hospitals and universities across the
country.
[2]
Nutrients Americans are Falling Significantly Short Of
Vitamin A
|
Calcium
|
Iron (females
of reproductive age)
|
Vitamin C
|
Choline
|
Folate
(females of reproductive age)
|
Vitamin D
|
Magnesium
|
Protein
(adolescents and older adults)
|
Vitamin E
|
Potassium
|
Vitamin B12
(older adults)
|
Vitamin K
|
Dietary Fiber
|
|
Here are some of the reasons you and many others may not be
getting enough of certain micronutrients:
- Following a popular diet that severely restricts
or eliminates specific foods or food groups
- Avoiding various food groups such as carbs,
dairy, meat and gluten due to preferences, allergies or intolerances
- Eating the same foods with little variety
- Cutting calories to lose weight
- Alcoholism, gastrointestinal disease, and eating
disorders
- Additionally, choline has been identified by nutrition
scientists as a nutrient of concern, especially during pregnancy and
breastfeeding. Most Americans don’t get enough, and it’s needed as part of the
structure of every cell in the body. 2
To learn what can happen if you’re not getting recommended
amounts of vitamins and minerals, check out
this article
.
B Vitamins and Weight Gain
It’s been
hypothesized
that excess B vitamin intake coupled with high carbohydrate intake lead to
converting more carbs into fat storage, thus resulting in weight gain. And
because many people consume the majority of their calories from carbohydrates, the
combination of B vitamins in our food supply and supplements has been
implicated as a potential contributing factor in the obesity epidemic.
Two published papers present observational data associating
the sharp rise in obesity with the fortification of foods with B vitamins.
[3]
,
[4]
However, with all observational research, a correlation between two variables
does not mean one caused the other or vice versa.
The old adage goes “correlation does not equal causation.”
This is a critical point when interpreting research and is often missed by
media outlets which deliver headlines to make the news. Consider the following:
Other occurrences that paralleled food
fortification and the rise in obesity include technological advancements, less
time spent outdoors, increased availability of food, more hyperpalatable
processed snack foods, more screen time, reduced physical education in schools,
and higher calorie intakes.
In order to determine whether excess B vitamins cause weight
gain and hence the rise of obesity, a randomized clinical trial would have to
be conducted in humans with two groups consuming the appropriate number of
calories to maintain their body weight. One group would be given a placebo, and
the other would be given extra B vitamins. At present, there is no such
research.
Vitamins and Weight Management
There is research that suggests that the use of
multivitamins may be helpful for weight management. One study was observational
in nature and looked at the use of a multivitamin and mineral supplement and
body composition and the other was a clinical trial in humans.
[5]
In the observational study, nearly 600 men and women were
studied and those who took multivitamins had lower fat mass and body weight
compared to those who didn’t take supplements. Interestingly, women who took
supplements reported feeling less hungry compared to non-users.
In the clinical trial, 45 obese individuals were randomly
assigned to one of two groups: 1) multivitamin and mineral or 2) placebo. Both
groups were asked to reduce their daily intake by 700 calories for 15 weeks. Here
are the results:
- Both groups lost weight, with no significant
differences between the groups
- There were no significant differences between
the groups in energy expenditure
- Women taking the multivitamin supplements
reported lower ratings in appetite
The researcher concluded the following:
“Overall, this suggests that an
appetite-modulating effect of vitamin and mineral supplements could be more
significant in individuals characterized by inadequate intake in micronutrients.”
Based on the data so far, it’s impossible to conclude that
excess B vitamins cause weight gain. It’s more plausible that adequate vitamin
intake may be helpful for appetite, particularly in women. As noted,
restricting calories for weight loss not only
worsens micronutrient inadequacies but also increases appetite.
Summary
The way we gain weight is by consuming calories above what
the body uses. Although vitamins and minerals are needed to extract energy from
the food we eat, B vitamins alone won’t result in weight gain. In fact, most
people are falling short of the various vitamins and minerals we need to support
overall health, metabolism and longevity.
Therefore, to prevent unwanted weight gain, consume a wide
variety of nutrient rich foods, and keep your calorie intake in balance with
your daily output.
By taking a complete multivitamin and mineral for your age,
gender, life stage and activity level, you raise the likelihood of getting all
the essential nutrients needed for optimal functioning of your metabolism.
Lastly, don’t use a multivitamin and other supplements as an
excuse to skip out on leafy greens, bright fruits and veggies and other
nutrient dense foods. Rather, use a full spectrum multivitamin to fill the gaps
and complement your food choices and avoid mega-dosing on vitamins unless a
licensed professional advises you to do so.
Do you want to see which multivitamin is right for you? Take our supplement screener questionnaire to find out.
References