are vitamin d recommendations too low? lisa hokanson dr...

Running head: VITAMIN D RECOMMENDATIONS 1

Are Vitamin D Recommendations Too Low?

Lisa Hokanson

Dr. Kimberly Brodie

December 16, 2015

VITAMIN D RECOMMENDATIONS 2

Introduction

Vitamin D is an essential part of anyone’s diet. Many assume that with all of the

fortification in foods and the fact our bodies can create vitamin D from sunlight, we do not need

to be concerned about insufficiencies (Davison & Hanley, 2005). This is not the case as about

41% of the United States population is at a significantly low level of vitamin D known as a

vitamin D deficiency (Forrest & Stuhldreher, 2011). “Typically, the prevalence of low [vitamin

D] levels is approximately 36% in otherwise healthy young adults aged 18 to 29 years, 42% in

black women aged 15 to 49 years, 41% in outpatients aged 49 to 83 years, [and] up to 57% in

general medicine inpatients in the United States (Holick, Hossein-nezhad, & Spira, 2006).” Some

of the risk factors for a vitamin D deficiency include limited time spent outdoors, living in the

northern states where there is less sun exposure, obesity or pregnancy, and having darker or

thinner skin (Vitamin D Council, n.d.). At such a high rate of occurrence, it is essential to

determine why people are not getting enough vitamin D and whether or not the determined levels

of intake are at a suitable grade to meet the needs of the United States population.

According to the National Institutes of Health, people who have a vitamin D deficiency

have less than 30 nmol/L (nanomoles per liter) of vitamin D in their blood but that level could be

all the way up to 50 nmol/L depending on the person (U.S. Department of Health and Human

Services, 2014). The recommended level is around 50 nmol/L but it is suggested that we may

need even more than that as our ancient ancestors required levels around 115 nmol/L (Dijck-

Brouwer, Kema, Kuipers, Luxwolda, and Muskiet, 2012). Although our bodies have changed

since ancient times and adapted more to the lifestyles we now live, we still need vitamin D to

live functionally and the levels we are recommended to reach are likely much too low than

previously deemed appropriate.


Purpose Statement

The current recommended level of vitamin D intake, as determined by the Centers for

Disease Control and Prevention (2012), is insufficient at 600 IU/day for adults and it needs to be

reevaluated for a level that will not result in such frequent deficiencies. Although it is very

difficult to get the recommended amount of vitamin D from just a healthy diet, supplementation

can fill the needed gaps if the right dose is prescribed or taken over the counter. This systematic

review aids in proving a lack of vitamin D, showing that there needs to be a reevaluation to

ensure people are getting the necessary intake to help eliminate preventable diseases as well as

demonstrate the many number of problems that result from a lack of vitamin D.

Research Question and Associated Hypotheses

In an effort to further understand the effects of vitamin D deficiencies, it is essential that

we evaluate and combine the studies that have already been completed to make connections and

find answers about the current levels of vitamin D intake. The research question investigated in

this systematic review is: Should the recommended vitamin D intake level for adults in the

United States be updated to a higher amount to prevent diseases and conditions that are a result

of a deficiency? The null hypothesis is that no change is necessary and the current level is

adequate. The alternative hypothesis reasons that a change in recommendation is preferable and

can help reduce serious diseases linked to a vitamin D deficiency.

Potential Significance

As vitamin D is studied further and we gain more understanding of its benefits, it has

become evident that without this vitamin, a greater number of people are suffering from major

chronic diseases and conditions. Some of these include kidney diseases, osteomalacia, psoriasis,


diabetes, and heart disease (Mayo Clinic, 2013). While much of the research regarding vitamin

D has been inconclusive and the actual effect it has on the brain is still being studied (Eyles,

Hewison, et al, 2005), it is affirmed that deficiencies of this vitamin in our diet presents a higher

risk of several extremely serious diseases such as Multiple Sclerosis (MS) and HIV/AIDS

(Vitamin D Council, n.d. a). In the case of Multiple Sclerosis, vitamin D plays a part in

connecting receptors in the immune and nervous systems as well as preventing inflammation in

cells (Vitamin D Council, 2014). Researchers are getting close to finding a definitive

relationship between vitamin D intake and the development of MS but it has already been

suggested based on research that children high in vitamin D are less likely to develop this

condition. That is a significant enough reason to ensure people are getting adequate vitamin D

without even considering of all the other diseases that are also linked to this vitamin. With

vitamin D deficiencies at 41% of the US adult population, it is growing to epidemic proportions

and unfortunately, the “correct” level of intake is potentially incorrect. This systematic review

has the potential to redefine the nutritional standard for this vitamin by revealing the prevalence

and impact of vitamin D deficiency on the US population.

Search Strategy

To find the most appropriate articles and studies for this review, two search engines were

used; EBSCOhost and PubMed. These engines were accessed in September of 2015 with only

articles dating back to the year 2005 used for this review. The terms used for finding the best

articles included vitamin D deficiencies, vitamin D deficiency, United States, and adults;

excluding children. These searches resulted in thousands of studies but they were easily deemed

relevant or not based on if they were studies and reviews (which were used) versus other less

relevant options such as results reviews or magazine articles from other countries.


Theoretical Foundation

The Theory of Planned Behavior is a theory that was developed in 1980 to explain what a

person’s intention is behind a behavior (Boston University of Public Health, 2013). It was

developed by Martin Fishbein and Icek Ajzen to explain the connection between attitude and

behavior as it seemed behavior was often determined by preconceived intentions that were

regularly influenced by others (University of Twente, n.d.). The theory connects behavioral

beliefs, normative beliefs, and control beliefs to determine someone’s attitude, social influence,

and perceived control of an action. Essentially, it finds the reason why someone does or does not

participate in a healthy decision and works to change specific aspects of the person’s thinking to

make for a more positive behavior. As an example, a study was recently published that found

people in Korea had a higher intent to continue working out at a gym if they were participating in

a sport that required other participants (Park & Song, 2015). The influence of other’s actions in

this study changed the intent of the subject’s actions thereby changing their behavior.

In regards to this systematic review, this theory seemed to be the most appropriate fit in

understanding the effects of vitamin D deficiencies and how it can impact the general public.

The majority of those who suffer from vitamin D deficiencies are not aware of this problem and

do not know what it can do to hinder one’s health. The Theory of Planned Behavior can analyze

why people do and do not get enough vitamin D in their diets and what factors lead them to

believe they do not need to be concerned about this vitamin. Also, it can be used to help

understand why current recommended levels are set at the suggested rate and whether or not it is

still an appropriate level for our society.


Literature Review

There are many physiological reasons why vitamin D is necessary and there have been

studies conducted to find how it connects with diseases. Vitamin D works closely with the brain

and the communication of cells and is also known to change the expression of certain genes to

avoid diseases (Holick, Hossein-nezhad, Spira, 2013). Although this is a relatively new subject

in the field of public health, vitamin D has many great qualities and is very important to

replenish.

To combat the problems that are arising with vitamin D deficiencies, it seems necessary

to reevaluate the recommended dietary levels and how people are getting this critical nutrient.

HIV patients are known to have this deficiency which can be easily altered if doctors screened

them at appointments (Brooks & Bush, et al, 2011). Also, people of certain races and ethnicities

are genetically more likely to have vitamin D deficiencies and therefore have greater health

problems as a result (Davison & Hanley, 2005). In a research trial where one group took the

recommended amount of vitamin D daily and another took double the recommended amount, the

second group was at a much lower risk of falls and breaks along with greater muscle mass and a

reduction in risk of cancers (Bischoff-Ferrari & Boucher et al, 2007). With these clear

improvements in health due to an increase in vitamin D intake, it should not be a question as to

whether or not the recommendations need to be reexamined. One of the next steps our society

needs to make in disease prevention is an increase in vitamin D intake.

Unfortunately, there are only a few studies that have been completed determining the

value of vitamin D and its effect on health. The struggle is to understand exactly how this

vitamin plays a role in the brain and scientists are unable to fully track its progression. There is

research which suggests the enzymes that make up vitamin D functions as cell receptors and


helps aid in communication between cells and the brain (Yetley, 2008). If there is not a sufficient

supply of vitamin D, these necessary processes are not performing correctly which results in

several diseases and conditions. This explains why inadequate levels of vitamin D can be

detrimental to a person’s health.

Methods

Vitamin D deficiencies are a significant problem in the United States and much of this

has to do with the unclear daily recommended intake. The Centers for Disease Control and

Prevention (2012) currently has the level at 600 IU a day but this is not enough for most and it is

difficult to get that much from food alone. By doing a systematic review, previous studies of

vitamin D and its effects on the US adult population were combined to determine if the

deficiency is a result of inadequate intake recommendations. There are many studies linking a

vitamin D deficiency with chronic diseases and conditions but by bringing them together, it is

determined whether or not our society needs to enact a higher recommendation to help lessen the

incidence of these diseases. This review is focused on adults in the United States who have a

vitamin D deficiency as well as studies on the effects of vitamin D and the recommended intake

level.

Inclusion and Exclusion Criteria

The two main search engines used for this systematic review were Academic Search

Premier and PubMed. There were other articles added later as found and deemed appropriate but

these were the two search engines used. The studies found were those published in 2005 or later

and involving adults, age 18-65, who were vitamin D deficient in the United States and who did

not have significant medical conditions. The elderly, children, and women who were pregnant

were all excluded as they generally require more vitamin intake than the general population (see


Table 1 below). The purpose of the review is to determine if the vitamin D recommendations

should be changed for the general population and the elderly, children, and pregnant women

have different and much more specific needs than the rest of the public so it seems appropriate to

exclude them from the review.

Table 1

Inclusion and Exclusion Criteria

Inclusion Criteria Exclusion Criteria

Vitamin D Deficiency “Older” or “Elderly”

adults

United States Children

Adults Chronic conditions

Since 2005 Pregnant women

Data Analysis Plan

To keep all of the information organized, Endnote X7 software was used which allows

for all selected articles from different databases to be compiled into one system. This enabled

the elimination of all duplicate articles and allowed for further filtering through the remaining

articles including the deletion of those not meeting the inclusion criteria. For example, there

were many studies initially considered that had subjects who were from foreign countries which

was not within the scope of the review. This software made it possible to go through the articles

multiple times to only have the most relevant articles used in the review. Figure 1 shows the

elimination process below.


Data Collection

Figure 1. Flowchart of article selection process.

In order to find the most beneficial articles to defend this systematic review, it became

necessary to do extensive filtering of the articles that were found during the original research

process. Although 62 studies were found to be relevant to the review, upon further examination,

only 12 studies were deemed appropriate for the results section based on the amount of data

Full-text articles excluded

for relevancy (n = 175)

Records identified through

database searching (n = 1463)

Additional records identified

through other sources (n = 9)

Records after duplicates removed

(n = 1409)

Records screened

(n = 1409)

Records excluded

(n = 1172)

Full-text articles assessed

for eligibility (n = 237)

Qualitative

Studies (n = 32)

Studies included in

systematic review (n = 62)

Quantitative

Studies (n=30)


available and the clarity of the methods and participant characteristics. Some of the studies

included in the group of 62 articles were more appropriate for the literature review or

introduction as they had good information but not sufficient data to support the purpose of the

review.

Results

Each of the 12 included articles are listed in the table below to provide a brief summary

of their study along with the intervention and outcomes. The actual data is listed in Table 3.

Additionally, this table provides a quality score which rates each article based on a set of

questions that shows how they rank in regards to clarity, focus, and limitations of the article.

This ensures that only the best articles are used because they have the information necessary to

be considered high quality.

Table 2

Characteristics of Included Studies

Study

(Authors’

name)

Setting Study

Design

n Population Intervention Primary

Outcomes

Quality

Score

Alvarez,

et al.

Emory

University

Campus

Randomized,

double-blind,

placebo-

controlled trial

28 Healthy adults

between 18-

65 years old

Each group

(experimental and

placebo) were given

5 identical pills with

experimental having

50,000 IU of vitamin

D. Periodic blood

draws determined

effectiveness of large

vitamin D doses

Large doses

were

effective in

preventing

seasonal

problems

but wore off

after 3

months

2


Barker, et

al.

LabCorp

facilities and

email

Retrospective

cross-sectional

study

743 Employees, or

friends or

family of

employees, of

USANA

Health

Sciences, a

manufacturer

of nutritional

supplement

Blood samples were

collected to

determine vitamin D

levels then surveys

were completed to

find sources of the

vitamin

Vitamin D

supplementa

tion was the

greatest

predictor of

vitamin D

status

5

Liu, et al. Using the

The 2007–

2010

National

Health and

Nutrition

Examination

Survey

Cross-Sectional 9719 Adults age

19+

Used previous data to

determine if vitamin

D levels are

dependent on

income,

race/ethnicity, or

gender

Category

with most

vitamin D in

their diet

was high-

income

white men

and lowest

was middle-

income

black men

4

Burnett-

Bowie, et

al.

Participants

were found

through

mailings and

newspaper/

Internet ads

Cross-Sectional 634 Volunteers

age 18-50

Participants were

each visited and a

blood sample was

taken. This was

immediately studied

for the vitamin D

level and they

answered

demographic and

habit-related

questions

64% of

participants

had levels

less than 30

ng/mL

4

Caporaso

, et al.

Orange

County, CA

Cohort 151 Residents of

Orange

County

between ages

18-90

Blood samples were

taken from all

participants to

measure vitamin D

level. Demographics

were also recorded.

19.2% of

participants

had low

vitamin D

levels

5

Connett,

et al.

Lung Health

Study

Nested,

matched case-

control study

196 Smokers with

decreased

lung function

Used data from three

previous studies to

find vitamin D status

among participants

31% were

vitamin D

defficient

5


Ameri, et

al.

California

laboratories

Randomized,

Placebo-

controlled,

double-blind

study

105 Healthy adults

age 18-84

Participants either

took vitamin D

supplements or drank

fortified orange juice

to determine which

was more effective

There was

no

significant

difference

between

those who

took

supplements

and those

who drank

fortified

orange juice

3

Booth, et

al.

Established

research

center for

Framingham

Study

Cohort Study 3890 Used results

from

Framingham

Heart Study

Blood samples were

taken and studied for

vitamin D level.

Additionally, the

participants were also

measured for adipose

and visceral fat levels

along with BMI

measurements.

Obesity is

linked to a

higher rate

of vitamin D

deficiency

5

Camargo,

et al.

National

survey data

Cross-sectional 18883

and

13369

Those willing

to take the

survey in the

US

population

Two National Health

and Nutrition

Examination Surveys

were compared for

vitamin D national

levels.

The US has

seen a

significant

decrease in

vitamin D

levels since

the surveys

conducted

1988-1994.

The mean

level

dropped

6ng/mL

5

Camargo,

et al.

National

survey data

Cross-sectional 15,148 National

survey

participants

Two NHANES

studies were

compared to

determine if physical

activity helped with

vitamin D levels.

Surveys and in-

person interviews

were conducted.

More

activity

resulted in

higher

vitamin D

levels

4


Alberts,

et al.

Tucson and

Phoenix

Cross-Sectional 619 Participants in

a colorectal

adenoma

prevention

study

Blood samples were

taken and

questionnaires were

answered about

participants’ habits

A significant

number of

adults in

Arizona,

where

people are

exposed to

more sun,

were

deficient in

vitamin D.

This was

especially

true for

blacks and

Hispanics.

4

Aloia, et

al.

Long Island Randomized,

double-blind,

placebo-

controlled

138 Healthy white

and black

adults age 18-

65

Different original

levels of vitamin D

determined the

category and amount

each subject was

given to raise to an

ideal level in six

months

People with

levels above

55 nmol/L

need 3800

IU to reach

an optimal

state and

those below

55 nmol/L

need 5000

IU

5

The information included in Table 2 supports the purpose of the systematic review by

providing studies that involved American adults who were relatively healthy. All of the articles

that were included met the inclusion criteria in that they focused on a significant number of

adults in the United States that did not suffer from extensive medical conditions. There were

many studies included in the searches that had subjects who had serious diseases or conditions

that were linked to vitamin D deficiencies but these were not included because the purpose was

to create a systematic review that was more easily transferrable to the general population. The


majority of the studies also had a higher quality score and included a significant number of

subjects which made the data more universal.

Table 3: Results of Included Studies

Author Quality

Score

Intervention Measures Results Statistically

Significant

Alvarez,

et al.

2 Each group

(experimental and

placebo) were given 5

identical pills with

experimental having

50,000 IU of vitamin

D. Periodic blood

draws determined

effectiveness of large

vitamin D doses

Mean plasma

25(OH)D

concentration

Plasma 25(OH)D

concentrations

improved for

experimental group

with increase of

24.69 ng/ml for five

days and only 1.37

ng/ml for placebo

group. No significant

changes for 90 or 365

days

P<0.001

Barker, et

al.

5 Blood samples were

collected to determine

vitamin D levels then

surveys were

completed to find

sources of the vitamin

Vitamin D

level, diet,

supplement

usage, latitude

of residence,

ethnicity, age,

and BMI

Depending on the

current level of

vitamin D, people are

recommended either

3800 IU or 5000 IU

to get their level back

within reason.

P<.05 –

Statistically

significant

depending

on season

Liu, et al. 4 Used previous data to

determine if vitamin D

levels are dependent

on income,

race/ethnicity, or

gender

Vitamin D

concentrations

and participant

characteristics

Higher vitamin D

was associated with

higher income, non-

Hispanic white

people. Women took

more supplements.

P≤.05

Burnett-

Bowie, et

al.

4 Participants were each

visited and a blood

sample was taken.

This was immediately

studied for the vitamin

D level and they

answered

demographic and

habit-related questions

Vitamin D

levels

Lower vitamin D

level predictors:

male, black or Asian

race, lack of

multivitamin use.

Seasonal variation

prevalent in all who

didn’t take a

supplement. Low

levels associated with

parathyroid and

skeletal diseases.

P<0.1

Caporaso,

et al.


taken from all

participants to

measure vitamin D

Vitamin D

concentrations

19.2% of Orange

County residents

were deficient

(<30pg/ml)

No p-value

recorded


level. Demographics

were also recorded.

Connett,

et al.

5 Used data from three

previous studies to

find vitamin D status

among participants

Vitamin D

levels

35% vitamin D

insufficient (≥ 20

ng/ml but < 30

ng/ml) and 31%

deficient (<20 ng/ml),

34% sufficient (≥ 30

ng/ml), and 7%

severely deficient

(≤10 ng/ml).

p<0.001

p=0.54

Ameri, et

al.

3 Participants either

took vitamin D

supplements or drank

fortified orange juice

to determine which

was more effective

Vitamin D

levels

Fortified orange juice

is just as effective as

supplementation at

providing vitamin D.

No

significant

difference

P = .084

P > .1

P = .82

Booth, et

al.


taken and studied for

vitamin D level.

Additionally, the

participants were also

measured for adipose

and visceral fat levels

along with BMI

measurements.

Vitamin D

levels and fat

indexes

Lower vitamin D

associated with:

Higher BMI,

Higher visceral and

subcutaneous adipose

tissues,

Insulin resistance

P < 0.005

P = 0.016

P < 0.0001

Camargo,

et al.

5 Two National Health

and Nutrition

Examination Surveys

were compared for

vitamin D national

levels.

Vitamin D

levels and

recreational

activities

No p-value

recorded

Camargo,

et al.

4 Two NHANES studies

were compared to

determine if physical

activity helped with

vitamin D levels.

Surveys and in-person

interviews were

conducted.

Comparison of

two studies

measuring

25(OH)D

concentrations

Mean level = 30

ng/ml (1988-1994)

Mean level = 24

ng/ml (2001-2004).

Levels <10ng/ml

increased 2% to 6%.

Levels ≥30 ng/ml

decreased 45% to

23%

p = 0.0005

Alberts,

et al.


taken and

questionnaires were

answered about

participants’ habits

Serum

25(OH)D

concentrations

25% of participants

were deficient, 22.5%

= 30 ng/ml,

25.4% <20 ng/ml,

2% <10 ng/ml,

Black (55.5%) and

Hispanic (37.6%)

<20 ng/ml with

Non-Hispanic white

P value <

0.05


at 22.7%

Aloia, et

al.

5 Different original

levels of vitamin D

determined the

category and amount

each subject was given

to raise to an ideal

level in six months

Serum

25(OH)D

concentrations

P < 0.05

All of these studies measured vitamin D levels and what potential influences and factors

cause deficiencies. The studies suggest that vitamin D levels are much too low for most

Americans regardless of location, even in Arizona where the sun is out much more than other

places (Alberts, et al, 2008). The table also shows that certain population groups are at a higher

risk of deficiency such as those of Black or Hispanic race (Liu, et al, 2014). One of the most

striking studies was done in 2009 (Camargo, et al) when researchers compared national data for

two National Health and Nutrition Examination Surveys comparing vitamin D levels of 1988-

1994 to levels of 2001-2004. They found that there was an average decrease of 6 ng/ml which

puts the population significantly below an adequate level. Most of the other articles included

provided support to this theory by recording the 25(OH)D concentrations of the participants and

discovering that a large number of participants were deficient; 35% (Connett, et al, 2011), 25%

(Alberts et al, 2008), and even 19.2% of Orange County residents (Caporaso, et al, 2011).

Figure 2: Results of systematic analysis.

There were no studies that suggested there

was no correlation between vitamin D

deficiencies and diseases. There was no

contradictory data; just a significant lack of this

essential vitamin.

All of the studies reported a significantly high

level of vitamin D deficiency among various

populations. They complemented each other

in their purpose and goal of proving that the

United States population is in drastic need of

additional supplementation of this essential

vitamin.


Discussion

Based on the evidence provided in the results, it is clear that adults in the United States

are at a critical state of vitamin D deficiency. With one study claiming 64% of their participants

being deficient (Burnett-Bowie, et al, 2012), 31% in another study (Connett, et al, 2011), and

19.2% of those in Orange County (Caporaso, et al, 2011), it is evident that something needs to

change because people are not getting this essential vitamin. It is not enough that they get

exposure to sunlight or eat foods high in vitamin D, they must also take a supplement in order to

achieve the highest potential intake and avoid major diseases that are being linked to a vitamin D

deficiency. This is undoubtedly a need that needs to be more adamantly addressed and explored

by the government in order to recommend a higher dosage of the vitamin.

Based on the data above, vitamin D deficiencies are very common and occur frequently

among those who are obese (Booth, et al, 2010) as well as men who are middle-income and of

African-American or Hispanic race (Liu, et al, 2014). Additionally, there has been a drop in the

average vitamin D level among the United States from 30 ng/mL to 24 ng/mL from the years

1988-1994 to 2001-2004 (Camargo, et al, 2009). The ideal level is at least 30 ng/mL but with a

drop of 6 ng/mL within 10-16 years, that is a 20% difference which puts a large portion of U.S.

adults at serious risk of major diseases and conditions. This is unacceptable and warrants a

professional reevaluation of how to change this trend.

Theoretical Implications

In order for people to change their actions to a higher intake of vitamin D, they must be

aware of their risk and accept that the change is beneficial and crucial. The Theory of Planned

Behavior is based on a person’s preconceived intentions toward a behavior so in order for them

to participate, they must first understand that they are potentially in a high risk group. By


understanding that a significant portion of the adults in the United States are at a high risk of a

deficiency, others can take the research included in this systematic review and find ways to

influence their community in participating in interventions that include high intakes of vitamin D

supplementation. The findings above provide a starting place for other public health educators to

develop interventions that can affect a person’s perceptions and eventually behavior in regards to

additional vitamin D supplementation. The data is a solid foundation that vitamin D deficiencies

are a growing problem within the United States.

Because the data in this review is based on separately conducted research studies, it is

essential that it be used as a support for a higher intervention and as a suggestion that

recommended supplementation regulations be reviewed. It should not be used as a standard for

what a new recommended level should be because no research studies were actually conducted.

It is suggested that it be used as a resource for the current state of vitamin D deficiencies for

adults within the United States.

Limitations

There are several potential limitations to this systematic review for consideration.

Although not every limitation can be listed, some include selection bias, database limitations,

language availability, and human error. Selection bias is a potentially high occurring limitation

considering several thousand articles were originally retrieved when searching for data but since

they cannot all be included in the study, some needed to be eliminated quickly. This possibly

resulted in articles being eliminated that could have supported the overall purpose of the study.

Additionally, only two databases were used in the study, both of which only included studies

written in English, which could have excluded significant studies that were in a different

language or not included in those particular databases. Lastly, human error could have played a


significant role in any part of the study. This study was created on a time limit so it is possible

that significant studies were missed or mistakenly deleted. Because of the listed limitations,

there is the possibility that the review is not as complete as it could be and that there are

confounding factors between the studies included. This may change the overall results but it is

believed that it would only be a minor difference.

As for specific studies, two of the studies included did not record p-values. This makes it

difficult to determine if the data reported is statistically significant. There is also the issue of the

quality scores as one study was included that had a score of 2 and the others had higher ratings

but the questions used to determine the score were very easily biased based on the researcher’s

evaluation of the study components. It is difficult to be sure that those were accurate scores or

that those eliminated based on quality scores were appropriately excluded.

Recommendations

Based on the research provided, vitamin D should play a greater role in our healthcare

requirements and concerns because of the benefits it provides and the clearly evident deficiency

we are suffering. With a decline of average intake from 30 ng/mL to 24 ng/mL in just 16 years

(Camargo, Ginde, & Liu, 2009), the adults of the United States are in need of continuing

guidance and education that will increase intake over time. There are many reasons why people

are not getting enough vitamin D including more indoor activities, less physical exertion, and

more processed foods. These issues need to be addressed by the appropriate parties to ensure the

level does not continue dropping. Further decrease will continue to facilitate additional chronic

health problems and therefore an overall decline in the United States’ health status.

As is evident from this review and the supporting data, there is a significant need for the

adult population of the United States to get more vitamin D through either their dietary intake or


additional supplementation. Unfortunately, there is not an adequate level of intake established

by government or public health officials because there has not been enough research to

determine how essential vitamin D is to the body and how fully it interacts with the brain and

other systems. Researchers are on the cusp of understanding its effects but further research could

solidify that the general population needs to make it a greater priority and find ways to add more

of the vitamin into their everyday diet. After finding those answers, more research needs to be

done to determine the optimal level of intake based on the ideal effects vitamin D can offer.

Implications for Social Change

Encouraging an adequate intake of vitamin D could potentially save millions of dollars

on healthcare costs annually as people take control of their preventative care and lessen their risk

of getting diseases related to a vitamin D deficiency. As is clear from the results, the adult

population in the United States needs a higher intake of this essential vitamin and there are many

positive benefits that can make for an overall healthier public. By starting now and educating on

the importance of supplementation, the next generation can grow to understand the mistakes of

their predecessors and understand that they need to be more aware of their vitamin D levels. In

the age of quick results and immediate satisfaction, it is important to take a step back and

understand the need to take care of long-term potential health issues and the future generations

may be in the best position to start anew and begin taking control of their health.


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