Nutrient sufficiency refers to our body’s ability to absorb the necessary level of micronutrients, vitamins, and other key substances that it requires. The nutrient content of people’s diets has declined significantly over time.  Globally, diets today are less diverse and are composed of a higher percentage of processed foods than ever before. Changes to our food and health systems aimed at achieving universal nutrient sufficiency can improve the lives of billions of people in developing and developed countries.

 

 

Overview

Nutrient sufficiency refers to our body’s ability to absorb the necessary level of micronutrients, vitamins, and other key substances that it requires. A being that is “nutrient sufficient” possesses the required nutritional status for a healthy and functional lifestyle. People who are not nutrient sufficient are in conditions of starvation, malnutrition, and obesity.  A person’s nutritional status affects their health, energy and concentration levels, immune response to infectious and chronic diseases, and productivity. Nutrient sufficiency is an outcome, not a set of inputs.  It requires the absorption, and not just the consumption, of necessary vitamins, minerals, proteins, and carbohydrates.

 

A society in which everyone is nutrient sufficient is considered nutrient secure. Nutrient security differs from food security because it incorporates an analysis of the nutritional status of beings. Food security refers to the availability of food and one’s access to it. A society cannot be nutrient secure without being food secure, but it can be food secure without being nutrient secure.

 

Nutrient sufficiency means more than the absence from hunger. Our bodies require microminerals and macrominerals in order to survive. Nutrients that are termed “essential” must be obtained from external sources because organisms cannot synthesize them or cannot produce the amount that is needed. A high proportion of people who are nutrient insufficient do have enough food to fill their stomachs but their bodies lack the necessary level of vitamins, minerals, and proteins.  Malnutrition is caused by a combination of factors: poor care and feeding practices; inadequate health services and unsafe water and sanitation; frequent infections or disease; and insufficient protein, energy, and micronutrients.[1] Deficiencies in iron, iodine, vitamin A, and zinc are the main manifestations of micronutrient deficiencies in developing countries.[2]

 

The nutrient content of people’s diets has declined significantly over time.  Globally, diets today are less diverse and are composed of a higher percentage of processed foods than ever before. In addition, the nutrient content of fruits and vegetables has declined significantly. This change over the past several decades is a result of changes in agricultural practices such as higher-yield production. Very often, essential nutrients are not readily available through people’s habitual consumption patterns.

 

Public health interventions to prevent malnutrition have not succeeded in achieving this goal. Among the most common approaches is fortifying staple foods with micronutrients such as iron. However, randomized controlled trials and reviews of national fortification programs have found disappointing results: fortification is largely unsuccessful.[3] Among the reasons that fortifications programs have been unsuccessful is because they have used forms of iron that are not bioavailable. Bioavailability refers to the extent to which a nutrient is able to be incorporated into the body’s functionality. The body does not recognize and absorb all micronutrients with equal success. In order to achieve nutrient sufficiency, people must consume adequate levels of nutrients that are in bioavailable forms.

 

Acute starvation, malnutrition, and obesity are all symptomatic of a lack of nutrient sufficiency. However, it is not currently possible to directly measure whether a person is nutrient sufficient. The current measurement procedures for malnutrition are based on body measurements (anthropometric parameters) and include body mass index (BMI) and mid-upper-arm circumference (MUAC). These assessments do not measure the presence in the body of the essential micronutrients in sufficient quantities to ensure health and wellbeing.

 

Given that it is not possible to measure the number of people who are and who are not nutrient sufficient, we must rely on population estimates based on anthropometric parameters and single-nutrient blood tests. It is estimated that over 2 billion people suffer from micronutrient deficiency in the world today. Malnutrition has been identified as the number one worldwide risk to health by institutions including the World Health Organization (WHO) and The Lancet.[4] Malnutrition and lack of nutrient sufficiency are especially problematic because they are part of a cyclical process that perpetuates sickness.  Malnutrition weakens the immune system, meaning that malnourished people are highly susceptible to infectious diseases.[5]  Concurrently, certain infections influence nutritional status and can cause a reduction in food intake and decrease the bodies’ absorption of nutrients.[6] Malnutrition also decreases people’s ability to concentrate and their intellectual capacity, which negatively affects school performance and worker productivity. The World Bank estimates that countries may lose two to three percent of their Gross Domestic Product (GDP) as a result of micronutrient deficiencies.[7]

 

Malnutrition is extremely detrimental to the health and economies of countries throughout the world. It is also preventable. Changes to our food and health systems aimed at achieving universal nutrient sufficiency can improve the lives of billions of people in developing and developed countries.

 

Impacts of Nutrient Non-Sufficiency

 

Lack of nutrient sufficiency has severe consequences. These consequences extend from the physical health of individuals to the economic health of a society. Malnutrition affects individuals’ ability to fight off serious diseases and increases their probability of facing serious illness and mortality. Children who are not nutrient sufficient have weaker school performance and adults have lower work productivity. At the same time that resources are diverted to treat malnutrition and its consequences, societies are simultaneously less productive, creating a dual-pronged reduction in national income. The consequences of nutrient insufficiency are both broad and deep.

 

Malnutrition increases the risk of infection and weakens the immune system. In fact, being underweight or undernourished accounts for more than half of the mortality risk from the most prevalent infectious diseases. One study concluded that 52.5% of all deaths in young children were attributable to undernutrition. The study found that the impact of malnutrition on disease-related mortality varies from 44.8% of measles deaths to 60.7% deaths due to diarrhea.[8]

 

Individuals who are not nutrient sufficient are at higher risk of morbidity and mortality associated with HIV/AIDS, tuberculosis (TB), and other infectious diseases because of malnutrition’s effect on the immune system. Lack of nutrient sufficiency is considered one of the primary risk factors in the onset of active TB. Additionally, malnutrition affects HIV transmission by increasing replication of the virus, decreasing the body’s ability to fight the pathogens, and increasing the risk of mother to child transmission.[9] In addition, a child born with low birth weight is also more likely to develop noncommunicable chronic diseases, such as diabetes and hypertension, later in life.[10] Lack of adequate nutrition is a major health threat due to its serious direct and indirect impacts.

 

Nutrient sufficiency is especially critical during the early stages of development. Both in utero and childhood malnutrition have long-term impacts on health. Medical experts agree that the damage caused by malnutrition during the 1,000 days of pregnancy and the first two years after birth can never be repaired. According to the WHO, adequate provision of nutrients, beginning in early stages of life, is crucial to ensure good physical and mental development and long-term health.[11] Consequently, malnutrition has a negative impact on cognitive development, school performance and productivity. Stunting and iodine and iron deficiencies, combined with inadequate cognitive stimulation, are leading risk factors contributing to the failure of an estimated 200 million children to attain their full development potential.[12] The education consequences of malnutrition are significant.

 

The economic consequences of malnutrition are also severe. Individuals who are not nutrient sufficient are less productive workers. They therefore are not able to earn wages that are as high as their nutrient sufficient peers. According to the WHO, eliminating anemia would lead to an increase of 5% to 17% in adult productivity.[13] Adults who were malnourished as children earn 20 per cent less, on average, than those who were not.[14]  In the aggregate, the impact on a national economy is substantial. The World Bank estimates that malnutrition reduces Gross Domestic Product (GDP) by 2-3%.[15] This economic impact is largely because people miss work and are less productive when they are not nutrient sufficient. Work absenteeism has a major impact on economic productivity. In addition, there is greater potential for worksite injuries when a person is not able to function at their full capacity.

 

The effect of malnutrition on the economy is also felt directly through high medical costs. Individuals who are nutrient insufficient require more medical services than their nutrient sufficient peers.  These services are extremely costly. The cost of medical services comprises a growing portion of national budgets, in both high-income and low-income countries. Private employers also bear a large portion of health-related costs. Additionally, the investment required to address the consequences of malnutrition diverts funds away from other important social causes.

 

Nutrient insufficiency has a detrimental impact on the health and economics of countries across the globe.

 

 

Measurement of Nutrient Sufficiency

 

It is not currently possible to test whether a person is nutrient sufficient. There is no mechanism for measuring their level of nutrient absorption for all of the relevant vitamins and minerals. There are blood tests for some important elements, such as iron, but there are not tests that are robust enough to measure the full range of vitamins and minerals that our bodies require. Substitute measures assess physical attributes but do not address nutrient absorption.

 

The current tools available for assessing malnutrition rely on body measurements. Anthropometric (body measure) parameters such as weight-for-age (W/A), height-for-age (H/A), weight-for-height (W/H), mid upper arm circumference-for-age (MUAC/A) and body mass index (BMI) are commonly used for assessing malnutrition and evaluating the effects of dietary treatment on children. Among these, BMI and MUAC are the most commonly used measurements.[16] The public health field continues to debate and study the best measurement among this group. BMI for age supplanted weigh-for-height as an index of thinness and overweight in the WHO 2007 growth references.  However, while there is supportive evidence for using BMI as a predictor of morbidity related to obesity, it is not substantiated as a superior indicator of malnutrition associated with poverty.[17] In famine situations, MUAC is often preferred over BMI to assess acute malnutrition of adults because it is less affected by fluid accumulation and does not require patients to stand upright.[18] The field continues to run trials and comparative analysis to determine the best substitute measurement for malnutrition.

 

All of the anthropometric malnutrition assessment methodologies described above are substitute measurements. They use the body’s physical attributes as indicators, but they do not directly measure nutrient levels.  In the absence of a direct measurement, we rely on these incomplete and inadequate indicators. However, it is essential to measure nutrient levels and the presence of nutrient sufficiency in order to determine whether a person requires a nutrition intervention. Without being able to measure nutrient sufficiency, it is not possible to assess whether supplemental foods or other protocols would improve a person’s health, mental capacity, and productivity.

 

 

Changes in Nutrient Content

 

One of the principal reasons that people are less healthy today is because our food is less nutritious. Vegetables and fruits are less nutritious today than they used to be. Micronutrients – vitamins and minerals – are what make produce so important to our diets. Unfortunately, our fruits and vegetables contain fewer and fewer micronutrients.

 

The United States Department of Agriculture (USDA) catalogues and publishes the nutrient content of fruits and vegetables. Several studies have compared this information across time in order to provide a historical perspective. In a review of USDA data published in 1950 and 1999, it was found that there was a statistically significant decline in the concentration of six important nutrients.[19] The six nutrients are protein, calcium, phosphorus, iron, riboflavin, and ascorbic acid. All are extremely important to our health. The median rate of decline for the nutrients ranged from 6% for protein to 38% for riboflavin. Many other studies have reached the same conclusion: our food is less nutritious today than it used to be. Three studies of historical food composition data found apparent median declines of 5% to 40% or more in some minerals in groups of vegetables.[20] The decreasing nutrient content is known as the “dilution effect,” signifying the reduced concentration of micronutrients in our produce.

 

There are several explanations for why the nutrient content of vegetables has decreased. The primary reason is changing agricultural practices. The “green revolution” of the 1960s and 1970s led to crop yields increasing by two- to threefold in major developing countries and by almost twofold in the United States.[21] Factors that led to increased crop yields include changes to cultivated varieties, use of fertilizers and pesticides, and irrigation practices. The incentive structure is responsible for these changes: farmers are rewarded for increased yield because they are paid by weight. Farmers are not incentivized to increase the nutrient content if their produce.

 

Research has shown that there is an inverse relationship between crop yield and nutrient concentration: as yields increase, nutrition concentration of produce decreases. Four side-by-side studies examined this phenomenon in various high-yield and low-yield variety crops and found that the relationship held true for every nutrient that was examined. This included two minerals in broccoli, six minerals in wheat, protein in wheat, and three amino acids in maize.[22] In addition, a review of 106 experiments on the effect of dry grain yields on protein concentration found that the negative relation between yield and protein concentration was fully substantiated for all cereals (including wheat, barley, oats, rice, maize, and sorghum).[23]

 

The decreased nutrient content of our produce is even more problematic because Americans do not eat enough fruits and vegetables as it is. The U.S. government recommends that people consume 2.5 cups of vegetables and 2.0 cups of fruit per day. However, Americans typically eat about half of this amount.[24]

 

Reduced nutrient content of our produce is extremely problematic, and even more so in a population that does not consume adequate amounts of vegetables and fruits.

 

 

Fortification

 

Fortification of staple foods is a commonly accepted answer to micronutrient deficiencies. The practice of fortifying cereal flours, primarily wheat and maize, is widespread in developing countries. Approximately 50 countries routinely add iron to flour.[25] Unfortunately, there is significant evidence that the current fortification programs are not effective in addressing their primary target of reducing the prevalence of iron deficiency anemia (IDA).

 

A review of iron fortification programs in the Americas found that there are significant technical and practical barriers that prevent effective implementation. Critiques included that “arbitrary criteria have often been adopted to select iron compounds,” “fortification programs lack quality assurance systems,” and “legislation has not been adjusted in accordance with needed changes to mandate fortification with specific sources.”[26] Significantly, the review also found that the most commonly used type of fortificant was not effective: “because of the widespread use of elemental iron powders (reduced and atomized iron) with uncertain bioavailability, these programs are likely to have limited impact.”[27]

 

There are several factors that must occur if a fortification program is to be effective: the target population must regularly consume the fortified food in high quantities, the supplemental micronutrient must be in a bioavailable form, the fortification process and its added element must meet very high quality standards, and monitoring and evaluation systems must provide reliable feedback loops. Unfortunately for the millions of people who are malnourished, it is very uncommon for these conditions to be in place.

 

Firstly, there is reason to doubt that target populations consume sufficient amounts of fortified foods in order for fortification programs to impact them. This is primarily a concern with regards to children. Young children in developing countries are at high risk for developing anemia but they often do not consume enough of the staples to benefit from fortification.[28] For this reason, it may be more effective to implement complimentary feeding programs, preventive supplementation, or other programs that directly impact the foods that children regularly consume.

 

Secondly, even when children consume the recommended amount of a fortified staple, there is evidence to suggest that it is not effective in reducing iron deficiency anemia. One study in South Africa used a randomized control trial methodology to examine the efficacy of iron fortification. Groups were randomly assigned to four different wheat fortification categories and all children received four slices of bread per school day for a period of 34 weeks. Some school children consumed bread fortified with electrolytic iron at the level currently used by the country in its national food fortification program. The study also assessed two alternative fortificants in the form of NaFeEDTA and ferrous fumarate. The results showed that none of the iron interventions affected hemoglobin (Hb) concentration, serum ferritin, serum iron, transferrin saturation, or serum transferrin receptor in any of the three groups.[29]

 

A second study in Kenya also found similar results. This study randomly assigned school children to four groups to evaluate the impact of fortified porridge. These groups were each routinely fed four different porridge compositions: unfortified whole maize flour porridge, and porridge fortified with high-dose NaFeEDTA (56 mg/kg), low-dose NaFeEDTA (28 mg/kg), or electrolytic iron (56 mg/kg). The children were assessed at baseline and throughout the intervention for various iron-related indicators. The study showed that only those children who consumed the high-dose NaFeEDTA showed improvement in their iron-status indicators.[30]

 

Given the significant resources that are invested in fortification programs, it is extremely concerning that they are not more effective in reducing micronutrient deficiencies. Alternative systems must be developed to both improve fortification programs and implement complimentary programming.

 

 

Bioavailability

 

In order for the body to benefit from nutrition, the nutrients must be in a form that the body can both recognize and absorb at the cellular level.  The body does not recognize and absorb all micronutrients with equal success. Bioavailability refers to the extent to which a nutrient is able to be incorporated into the body’s functionality.

 

The commonly accepted definition of bioavailability is the proportion of the nutrient that is digested, absorbed and metabolized through normal pathways.[31] In other words, bioavailability is the proportion of a nutrient that is available for immediate use or storage.

 

The concept of vitamin and mineral bioavailability for dietary supplements does not have a standard scientific or regulatory definition.[32] This is partially due to the complexity and variability of the many factors that influence the extent to which our bodies absorb and excrete micronutrients.

 

There are many factors that influence our bodies’ ability to absorb micronutrients. These factors relate to biological functions, characteristics of the nutrient, and extrinsic variables. Variable biological functions include intestinal absorption, excretion of glucuronides, metabolism by the microflora, intestinal and hepatic metabolism, plasma kinetics, cellular uptake, intracellular metabolism, accumulation in tissues, and urinary excretion.[33]

 

Individual characteristics also impact our ability to absorb and our propensity to excrete micronutrients that we consume. Examples of these variables include age, sex, nutritional status, and physiological state.[34] For example, bioavailability can change during pregnancy and lactation as the nutrient needs of women increase and physiological adjustments that are made to meet those needs alter the fraction of ingested nutrient retained.

 

The amount of a micronutrient that is consumed also affects our absorption and utilization rate. For example, the absorption of calcium varies inversely as the logarithm of the load size.[35] Equal levels of absorption in themselves do not ensure equal biological effects and nutrient activity since nutrient sources are chemically different.[36]

 

The form of a micronutrient is also an important determinant of its bioavailability. In many cases, the form of a micronutrient is as important as the total amount consumed in influencing the amount that the body absorbs.  Micronutrients can be in mineral or chelate form. Chelates are chemicals that form soluble, complex molecules with certain metal ions. Chelates inactivate ions so that they cannot react normally with other elements to produce precipitates or scale. They are a highly bioavailable form of minerals.

 

The bioavailability of iron is a good example of how the form of the mineral affects the body’s ability to absorb the nutrient. There have been several studies looking at absorption of different forms of iron. These studies have consistently shown that the proportion of iron that the body absorbs is higher from the chelate form than from ferrous sulfate.[37] One study determined that the bioavailability of bis-glycinate chelate iron was 90.9%, compared to 26.7% for ferrous sulfate.[38] Another study found that iron absorption from the chelate was approximately twice the absorption from ferrous sulfate.[39]

 

Similarly, studies have shown that the amount of iron that is absorbed varies between food sources. For example, the iron is breast milk is more bioavailable than iron in infant formula. One study of 256 newborns found that breast-fed infants absorbed an average of 49% of a trace dose of extrinsic iron, in contrast to the approximately 10% reported to be absorbed from cow milk.[40] Other studies have also found that breast milk is more bioavailable but by smaller magnitudes.[41] Infants require significant amounts of iron for the synthesis of blood, muscle, and other tissues required for their rapid growth. Given their growth needs and the small quantity of food that they are able to consume, the form in which they receive micronutrients is critically important.

 

The relative bioavailability of food items is an essential component of nutrient sufficiency, as it significantly affects the quantity of micronutrients that bodies are able to absorb.

 

 

Conclusion

 

Achieving nutrient security is one of the most important challenges facing us today. The health of populations and strength of economies hinge on our society’s ability to ensure that everyone has access to nutritious food. Universal nutrient sufficiency requires significant changes to agriculture, food, health, and economic systems. The results will be worth the efforts. Ensuring that bioavailable, nutrient-rich food and food supplements are available to the world’s population will change the health of our world.

 

 

 

 

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