Childrens Nutrtional Requirements

The British Journal of Nutrition devoted a supplement to the topic of Nutritional needs of children. This is a must read for nutritionists. ( BJN Vol 92, Supplement 2 October 2004 pp S 67-232)

This report based on two expert committees and gives an overview of the analysis of children’s nutritional needs in Europe. The data currently is diverse, based on a wide range of national criteria and often extends only to age 2years.

The nutrient needs of children include high and specific needs for nutrition particularly at times of rapid growth, infancy , pre school period and pre-pubertal period. Children have needs based on gender, metabolic needs including turnover, growth development and differentiation, physical activity and eating patterns and changing body composition with age.

The child is not a small adult but a future adult.

They have high metabolic demands but little body storage capacity, very much a just on time provision. As the modern child has quite an long expectation of life the laying down of healthy tissues is important.

Values for children are often extrapolated from adult values on a data per body weight or body surface area. The problems are compounded by the sometimes poor data that the calculations are based on.

Terminology is also a problem, Population Reference Values, Reference Values for Nutrient Intake , Dietary Reference Intake are used in different parts of Europe. . The use of these reference values vary.

Reference values are used for labelling of nutrient content of foods. Or recommending food intakes for populations.

It is also important to know what should be and what is actually eaten in the face of over eating and the current high prevalence of Obesity.

The eating patterns of children are changing across Europe. More time is spent watching television ands snacking. The orderly pattern of breakfast, lunch and evening meal consisting of home made foods may no longer be the pattern for many. The portion size of prepared foods is increasing. Overweight is not necessarily due to eating too much food and the problem is clearly complex.

The review gives detailed data for all nutrient requirements, country to country.

Food and eating habits are changing across Europe especially with a more global view and also better economic status. . Water intake and how the water is drunk is important, and need to be calculated along with metabolic water. Sugary soft drinks, tea or plain water will have a different impact on the person. Also the ambient temperature and physical activity will influence water needs

The diet may influence cognition and behaviour in children. Whether or not the child eats breakfast is important.

Countdown 2015

The Lancet for April 23 2008 is largely devoted to the Countdown programme for 2015. This initiative is so important for the poor countries of the world.

Of enormous importance for our world and the future of the populations.

The features of the Countdown Initiatives are

Country Focus Individual country profiles of coverage with selected information about the demographic and epidemiological contexts and key determinants of coverage.

68 priority countries 68 countries with the highest burden of maternal and child mortality, which represent more than 97% of all such deaths

Coverage of interventions within the continuum of care.

Tracking coverage of interventions with evidence of effects for maternal, newborn, and child survival, which tan be delivered within the continuum of care, the core of a functioning health system

Continuity Countdown will continue to report on progress until 2015, the target date for the Millennium Development Goals

Independence yet wide ownership

An effort, involving UN agencies and Civil society, individual researchers, and development worked from country, regional, and international levels

Action-oriented Countdown amalgamates the information needed to assess progress and spur country level action to accelerate progress towards reduction of maternal, newborn, and child mortality and improved nutrition

Countdown 2015

Dietary supplement survey. Harrison et al Brit Journal Nutrition 2007, 91, 617-23.

The authors of this paper surveyed 21923 adults asking them of their usage of dietary supplements along with a self assessment of health and twelve item general health questionnaire in the Bolton and Wigan area of Lancashire. They were also asked about exercise, smoking and fruit, vegetable and fish oil intake Their ethnic and social and economic status was also asked for.

A mammoth and important study.

Over 95% of replies were from white adults.

Over one third ( 35.4 %) took supplement. This group tended to be older, female, homeowners, , none smokers, physically active and white. The use of vitamin supplements was often in association with five pieces of fruit and vegetable a day. Taking fish oil supplements was in addition to one oil rich fish a week.

Those who took these supplements were physically fitter. There was increased

usage of fish oils in individuals troubled with musculoskeletal problems.

Individuals with cardio vascular diseases tended not to take any supplements.

The official view amongst Dietetic experts is that most people eat a diet which makes supplementation unnecessary. Ignoring the wish to do something natural, prudent , sustaining and cosseting to be healthy.

This is a practice generated by Nutrition literature and acted upon by the thinking public. Even if their logic is not totally correct. It would be very interesting to know how the individuals decided to take a supplement. Gossip over tea or Bridge, daughters fussing over their Mums or reading magazines . Or none of the above.

Eating Fish

Khursheed N Jeejeebhoy has reviewed the benefits and risks of a fish diet and should we be eating more or less?

Omega-3 fatty acids, eg eicosapentaenoic and docosahexaenoic acids which are plentiful in fish oils may preventing coronary artery disease. Eating three fish meals a week reduces risk in contrast to ineffectual high-fibre and low-fat diets did not have a significant reduction in mortality. Many trials have since shown the benefit of taking fish oil. This cardioprotective benefits is found with both wild and farmed fish.
. The consumption of as little as one fish meal weekly has been shown to be beneficial, with dose-dependent greater benefits up to about five fish meals per week.

The caveat to this simple diet change has been the suggestion of a risk of mercury poisoning of the central nervous system.

Mercury enters the atmesphere by combustion of waste and coal. The element then enters the oceans from the atmosphere where it is converted to methyl mercury by microorganisms and then taken up by marine life and concentrated in fish. As methyl mercury is not fat soluble, unlike dioxins, it does not accumulate in the fatty tissues. Methyl mercury is strongly neurotoxic.

The concentration of methyl mercury in fish b increased by fish eating other fish for food. Fish that are not predatory, such as sardines, salmon and shrimp, therefore have very low levels of methyl mercury. By contrast, predatory fish such as shark, tuna, swordfish and orange roughy have higher levels of methyl mercury. Farmed fish have the lowest levels of methyl mercury. Whilst methyl mercury per se is very neurotoxic, in fish methyl mercury is bound to cysteine, and this compound has a tenth of the toxicity of pure methyl mercury.

Whale meat is enriched with methyl mercury and is more neurotoxic..^

The conclusion is that in the amounts eaten in North America fish is very safe and the benefits large. That in pregnancy care should be taken with the eating o shark, tuna and sword fish.

Jeejeebhoy 2008, Benefits and risks of a fish diet-should we be eating more or less. Nature Gastroenterology and hepatology vol 5, pp 178-179

Height And Culture

In most surveys quantitative data are gathered with questionnaires and interviews. A comparison of such self reported data

with measured equivalents shows that people systematically underestimate or overestimate frequencies (cigarettes smoked daily, age of onset, time to pregnancy) or clinical parameters (height, weight, blood pressure). This may occur because participants intentionally or unintentionally round figures to a preferred end digit. Bopp et al analysed the preference for the end digits zero and five when reporting height. Since height is overestimated in almost all cultures (with variable magnitude) people who round to zero and five probably overestimate rather than underestimate their height .

Their results show shows similarities between languages belonging to the same family. People speaking Germanic (and possibly Slavic) languages indicated the end digits zero or five consistently less frequently than did people speaking a Romance, Greek, or Semitic language. In a large and representative Swiss sample, people kept the end digit preference characteristic for their native language even when living in a region using a different language, suggesting that such preferences are inherent in culture. This cultural bias might be particularly important when analysing trends in countries with high cultural preferences for rounding numbers and this could mask or exaggerate real differences between populations and could also explain why differences between measured and self reported estimates vary between cultures.

This is a real lesson for international surveys where countries are compared.

Bopp et Faeh 2008. Who gives me fives? BMJ vol 337, 1463

Infant Survival

During 2008 the Lancet has run a fascinating series of articles on malnutrition and deprivation. These are profound contributions to our understanding and knowledge.

There is of course correspondence coming in to the Lancet concerning these articles and reveal the complexities of straight forward and sensible ideas.

Bhutta at al Lancet 2008 vol 371 pp 417-40 wrote about the Intervention for maternal and child undernutrtion and survival.

Amongst the issues raised was the value of vitamin A supplements within 3 days of birth and subsequent survival. Quite separate was the issue of supplementation after 6 months.

Bhutta et al studied all available papers. The problems of interpretation appear to be multiple and include the quality of the studies. Also as pointed out by Sachdev Lancet vol371 p 1746 that there is a risk of ignoring negative or neural results onl y looking at positive results. As yet unpublished papers are also a problem.

There is no problem about the value of vitamin A supplementation for the 6 months plus infant, the value is real.

For the new born the value is uncertain. This raises the possibility that the newly born can be protected by stores coming directly from their mother in the womb.

There are differences between children in Africa and Asia in the prevalence of kwashiorkor. This affects 2.5% of 1-3 year olds in Malawi in the maize eating communities. These babies are liable to develop metabolic failure, heart failure rather than s imple wasting.(Ndekha Lancet vol 371 p 1748 )

The basic problem is one of nutrition and available clean nutritious food.

Millenium Statistic Goals

Nutritionists and other Professionals use statistics to help decide what is best for the general public. This is a very important paper in Lancet setting out the principles that are necessary for good practice. (Murray Lancet 2007, vol 369, 862 -73)

Towards good practice for health statistics: lessons from the Millennium Development Goal health indicators

Health statistics are at the centre of many global health controversies. Several factors are influencing the supply and demand for high quality health information. The health-related Millennium Development Goals give a good ex ample.

Thousands of indicators are recommended but of them are well measured. The international health community needs to focus its efforts on improving measurement of a small set of priority areas. Priority indicators should be selected on the basis of public-health significance and measurability.

Health statistics can be divided into three types: crude, corrected, and predicted.

Health statistics are prerequisites for planning and strategic decision making, programme implementation, monitoring progress towards targets, and assessment of what works and what does not.

Crude statistics that are biased have no role in any of these steps; corrected statistics are preferred. For strategic decision making, when corrected statistics are unavailable, predicted statistics can play an important part.

To monitor progress towards agreed targets and assessment of what works and what does not, however, predicted statistics should not be used.

The most effective method to reduce the controversies over health statistics and to encourage better primary data collection and the development of better analytical methods is a strong commitment to provide an explicit data audit trai l.

This initiative would make available the primary data, all post-data collection adjustments, models including covariates used for farcasting and forecasting, and necessary documentation to the public.

Definitions of technical terms

Indicator

A variable measured to monitor progress or assess what works and what does not.

Validity

Validity refers to the extent to which a measurement is capturing what it is intended to measure. There are different types of validity such as face validity, content validity, criterion validity (denoting predictive validity and concurrent validi ty), and construct validity (denoting convergent and discriminant validity).

Reliability

Reliability refers to the repeatability or consistency of a set of measurements or measuring instrument, for example, test-retest reliability where a test and a retest are compared.

Comparability

Measurements arc comparable if the same value means the same thing in the settings being compared. Two thermometers, one in Farenheit and one in Celsius, can both be valid and reliable but they do not give comparable results.

Out-of-sample

Prediction about ranges of values that are not in the investigator’s sample (ie, that the investigator’s data set does not cover).

Out-of-time

Prediction about individuals, populations, etc, in time outside

the time range of the investigator’s sample.

Forecasting

Forecasting is the process of estimation in unknown situations. Predicting is a moie general term and connotes estimating for any time series, cross-sectional, or longitudinal data Forecasting is commonly used when discussing time series data.

Farcasting

Farcasting is trying to predict the value of a variable in a place that may be far away but is not a future value.

Prior

The prior is a reflection of some information the investigator has before the observations in the data set (the investigator should state explicitly how the information on the prior was obtained). The prior is the sum of what is known about the re lationship under study.

Murray Lancet 2007, vol 369, 862-73

Key events dose response framework

The September edition of Critical Reviews in Food Science and Nutrition ed Fergus Clydesdale( vol 49 issue 8 ) is devoted to Key events Dose Response Framework.

This is a systematic review of key events which occur between the initial dose of a biologically active substance and the effect.

The substance will be

1. ingested, absorbed ( which is liable to be modified by events in the intestine and stomach.)
2. transported or processed by metabolism
3. a interaction or process in the target tissue
4. ultimate effect of interest.

The evaluation of the benefits and risks of a chemical depend upon a knowledge of the dose response in the recipient. A threshold dosage for the biological effect may be defined.

However each human is individual and the biology and genetic make up will differ so it is important to be careful in being too specific about a response. The number of individuals studied, he sensitivity of the methods used to test the chemical’s effect and the frequency and length of the study measurements are important.

The concept of Mode of Action (MOA) is discussed. . A mode of action is a biologically plausible sequence of key events, starting with the interaction of an agent with a cell leading to a observable biological effect. A key event is an observable precu rsor step that is a necessary part of the mode of action.

The authors believe it is important to define these key events for any biological process.

Finally the review applies these principles to nutrition specifically vitamin A.

Julien et al 2009 The key events dose-response framework: a cross-disciplinary mode- of action base approach to examining dose-response and thresholds. Critical Reviews in Food Science and Nutrition ed Fergus Clydesdale vol 49 pp 682-689

Boobis et al 2009 Application of key events analysis to chemical carcinogens and non-carcinogns. Critical Reviews in Food Science and Nutrition ed Fergus Clydesdale vol 49 pp 690-707

Ross et al 2009 Applcation of a key events dose response analysis to nutrients: a case study with vitamin A ( retinol ) Critical Reviews in Food Science and Nutrition ed Fergus Clydesdale vol 49 pp 708-715

Molecular Targets

In a very interesting paper in Nature , Keiser et al discuss methods of predicting molecular targets for new drugs. It is a comprehensive review of drug – target interactions. Drugs are intended to be selective but often bind to several physiological targets which cold explain side effects and efficacy. The authors selected 3665 drugs and compared these against hundreds of targets defining each target by its ligands. A ligand is a molecule or part of a molecule which binds selectively to one or more specific sites in another molecule eg hormone with receptor. Chemical similarities between drugs and ligands predicted thousands of unanticipated associations. These were than tested in experiments and in a smaller series significant new actions were discovered.

What an opportunity there is for nutritionists to make similar studies with nutrients for example the vitamins and trace elements

Keiser et al 2009 Predicting new molecular targets for known drugs. Nature vol 462 pp 175-181

Hopkins 2009 Predicting promiscuity Nature vol 462 pp 167-8

Nutrition Advise 2007 —

Interesting and relevant dietary advise is available from the work of Kay-Tee Khaw and colleagues based at the University of Cambridge and the MRC Unit.

They questioned 20,000 healthy adults aged 45-79 about their life styles and measured their blood vitamin C concentration as a measure of fruit and vegetable intake.

They gave values between 0 and 4 for a series of healthy behaviours and then followed the participants for a period of time and recorded their death ( 0 being absence of a healthy behaviour, 4 being good )

People with low scores were much more liable to die of coronary heart disease than those with high scores. Low scorers were also liable to die 14 years earlier than those with high scores.

In order of impact the life style benefits in order best to least benefit, albeit still of benefit was

Not smoking

Eating fruit and vegetable

Moderate drinking and exercise.

It has long been known that smoking can educe life expectation by 11 years on its own

This was reported by Reuters and published in PLoS medicine.

In Melvin Braggs Newsletter 20th December he quotes Noga Arikha who has written a book

Passions and Tempers: a history of the humours, an ancient belief in medicine.

Each humour traditionally had specific characteristics, for instance:

Choler, or Yellow Bile

Predominant in those endowed with a choleric temperament

. element: fire

qualities: hot and dry .

colour: yellow

taste: bitter .

season: summer

time of day: midday .

body organ: spleen .

period of life: youth .

signs: Virgo, Leo, Cancer .

planet: Mars

In a balanced person, the predominance of choler ensured a reactive and quick-tempered character. A choleric was typically able to make decisions well and fast, and preferred action over contemplation. But a surplus of choler could become “burned” and eventually turn into melancholy (melan=black, choler=bile, in Greek). Character could also become acrid and negative; reactivity might then be directed at the wrong objects. This sort of choleric could get angry easily and have episodes of uncontrolled, potentially dangerous rage. As Brutus exclaimed to Cassius in Shakespeare’s Julius Caesar (IV, 3): “Must I give way and room to your rash choler? Shall I be frightened when a madman stares?

She does the same for melancholy and for blood and for phlegm.

This demonstrates that you had a life system through the four humours, giving your place in the universe, on the planet and inside your own skin.

Standard remedies for melancholia and other complaints included playing soothing music, taking baths, drinking broths and herbal infusions, applying leeches, and taking potions and pills – made with everything from mint and saffron to turpentine. Some of the remedies worked, others didn’t and some had the opposite effect and ended up killing the patient.”

What is new.

Reference Values Children —

Energy and reference values for European Children ( Prentice A et al Brit J Nutrition 2004, 92, S83-S146

National reference values for children aged 2 to 18 years across Europe are very varied.

The formulation of dietary reference values and nutritional recommendations require an understanding of the physiological requirements of a healthy individual.

The best definition of a physiological requirement should be

1.the amount and chemical form of a nutrient to maintain normal health and development without disturbance of the metabolism of any nutrient. An intake sufficient to meet physiological requirement which will differ between individuals

2. the amount of the nutrient or energy that will meet needs, in the environment in which the community lives using local foods.
The purpose of nutritional reference values is to maintain and promote health and quality of life, and the vital metabolic and psychical and psychic functions in nearly all of the healthy individuals population. It is desirable to allow for the establishment of suitable body stores. Also to prevent nutrient-specific deficiency diseases .and deficiency symptoms.. but not in excess.

Central to the dietary reference values and recommendations is an understanding of the bioavailability of dietary nutrients; that is how much actually gets into the body and is available for metabolic and physiological functions. Bioavailability means the whole of absorption, distribution, metabolism and excretion. Bioavailability is affected by the composition of the diet, the chemical form of the nutrient and the nutritional status of the individual regarding that nutrient.

Bioavailability varies with age, with physiological state (e.g. puberty, pregnancy, lactation) and with nutritional status. For example, the absorption of many minerals increases during puberty and pregnancy, and excretion decreases. Metabolic adaptation in individuals with small body stores can lead to increased absorption efficiency in some situations but can also lead to smaller physiological requirements in others. Physiological requirements differ between different organ and tissues of the body. A good example of this is the active transport of nutrients across the placenta in pregnancy.

The term Recommended Dietary Allowance for a nutrient was first used in 1941 to enable food rationing to be a safe policy for the population. The definition is the average amount of a nutrient which should be provided per head of a group of people if the needs of practically all of the population are to be met. Recommended has now been replaced by ‘reference value”.

Different countries have defined nutritional requirements, recommendations and reference values, and nutritional guidelines for their own populations. The guiding principle being that physiological requirements differ between individuals and that the handling of nutrients by the body may be substantially affected by environmental and individual factors.

The Scientific Committee on Food of the EU defined three reference values to describe the distribution of required dietary intakes within age- and gender-specific subgroups of the population:

The mean intake to meet the average physiological requirement, the Average Requirement (AR);
The 97.5th centile (mean + 2SD>, the Population Reference Intake being “the
intake that will meet the needs of nearly all healthy people in the population or group”
The 2.5th centile (mean-2SD), the Lowest Threshold Intake , the intake
below which nearly all individuals in the population or group will be unable to maintain metabolic integrity according to the criterion chosen”.
The UK used different terminology for the three Dietary Reference Values (DRV):

Estimated Average Requirement (EAR);
Reference Nutrient Intake (RNI = EAR +2SD)
Lower Reference Nutrient Intake (LRN1 = EAR —2SD).
All the definitions assume that the distribution is normal so that the standard deviation can be used to describe upper and lower values.

The USA/Canada, the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes (Food and Nutrition Board. 1997) adopted a similar framework for the derivation of Dietary Reference Intakes

Estimated Average Requirement (EAR) as ‘the average daily nutrient intake level estimated to meet the nutrient requirement of half the healthy individuals in a particular life stage and gender group”;
Recommended Dietary Allowance (RDA) as “the average daily nutrient intake level estimated to meet the nutrient requirement of nearly all (97 to 98 per cent) healthy individuals in a particular life stage and gender group’.
When there is insufficient data to confidently give a recommendation the US/Canadian committee defined Adequate Intake (AI). , the “recommended average daily nutrient intake level’, to be used ‘when an RDA cannot be determined’

In recent years, the concept of an upper limit has been introduced, to define nutrient intakes which might be excessive and detrimental to health,. In the EU . an Upper Tolerable Nutrient Intake Level and the USA/Canada (Food and Nutrition Board. a Tolerable Upper Level

Food Balance Sheet and Health —

Worldwide dietary data for nutrition monitoring and surveillance are commonly derived from food balance sheets (FBS) and household budget surveys (HBS).

This is important as specifically designed individual nutrition surreys are both expensive and labour intensive and require skill and co-operation.

In this huge study et al have compared food supply from FBS and food availability data from HBS among eighteen European countries and have estimated the extent to which they correlate, focusing on food groups which are comparably captured by FBS and HBS and for which there is epidemiological evi¬dence that they can have a noticeable impact on population mortality. Spearman’s correlation coefficient was +0•78 (P< 10-3) for vegetables (including legumes), + 0•76 (P< 10-3) for fruits, +0•69 (P< 10-3) for fish and seafood and +0•93 (P< 10-3) for olive oil.

With respect to meat and meat products, the coefficient was lower at +0•39 (P=0•08).

The writers have examined whether the supply (FBS) or the availability (HBS) of food groups known or presumed to have beneficial effect on the occurrence of CHD and total cancer can predict overall, coronary and cancer mortality in ecological analyses. After controlling for purchasing power parity-adjusted gross domestic product and tobacco smoking we found that for vegetables, fruits, fish and seafood, as well as for olive oil, both the FBS and the HBS estimates were inversely associated with total mortality, coronary mortality and cancer mortality, although the number of countries with complete information on all study variables hindered formal statistical documentation (P>0•05 in some instances).

FBS and HBS have their own strengths and weaknesses, but they may complement each other in dietary assessments at the population level.

Naska et al 2009 Food balance sheet and household budget survey dietary data and mortality patterns in Europe. British Journal of Nutrition vol 102 166-171