oxidation of nutrients

The effect of chemical reactions and food is an interesting topic.
A summary in Seal et al BJN 2008 vol 99, supplement 2 is useful
OXIDATION unsaturated acids
Polyphenols and carotenoids
Vitamins
The consequences may be loss in nutritional value and changes in biological potency, sometimes formation of toxicologically suspect compounds.
MAILLARD REACTIONS .
Reducing sugars, amino acids, proteins
The effect is on the taste and flavour of food, browning of the food, loss of amino acids e.g. lysine and formation of toxicological suspect compounds
Β-ELIMINATION
Biopolymers e.g. pectins with texture loss
GELATINISATION texture and digestibility changes.

Seal et al 2008 Risk benefit considerations of mitigation measures on acrylamide content of foods-a case study on potatoes , cereal and coffees. BJN vol 99 supplement 2

vitamin A supplementation and infant survival

If ever there was work in progress it is on the topic of vitamin A supplementation in newborns and child survival. Vitamin A supplementation at 6-72 months of age has become a mainline intervention for improving survival in poverty stricken populations. Giving vitamin A supplements to newborns in the first days of life in Asian babies has benefit for survival But in African babies. Yet giving at 1-6 months has no benefit.
Studies in Africa and Asia produce different results and answers.
Here is a real conundrum, so the advise is supplementation ( 50,000 IU ) after 6 months but earlier is unjustified in general but time will tell.
Tielsch 2008 Vitamin supplementation in newborns and child survival , vol 336, pp 1385-1386
Benn et al 2008 Effect of 50,000 IU vitamin A with BCG vaccine on mortality in infants in Guinea-Bissau: randomised placebo controlled trial BMJ vol 336 pp 1416-20

maternal vitamin B12 deficiency and neural tube defect risk

Ray and colleagues raise an important point on folic acid fortification. This is a very contentious subject, with well developed battle grounds.
Folic acid fortification is advocated to prevent or reduce the incidence of foetal neural tube defects in babies. A terrible blight for those afflicted.
Folic acid fortification was universally introduced in Canada in 1998 , the result was a 50% reduction in foetal neural tub defects.
However why has the figure not dropped to zero?
The authors show that 35% of neural tube defects in Canada may be a result of maternal deficiency of vitamin B12.
7.4% of pregnant women tested in a study in Ontario had a reduced serum B12 concentration.
Clearly an important trial is required here of vitamin folic acid and folic acid plus B12 supplementation
Ray et al 2008 High rate of maternal vitamin B12 deficiency nearly a decade after Canadian folic acid flour fortification QMJ vol 101 475-477. .

synergy and oncogenic genes

The transformation of a normal cell into one with malignant properties requires the cooperation of a few oncogenic mutations that change cell features and induce complex changes in gene expression patterns.
McMurray and colleagues has shown ( in an article in Nature 2008 vol 453 pp 1112-1115 ) that cell transformation depends upon synergistic modulation of down stream signalling circuitry. Hence maligancy is a highly cooperative process involving synergy at multiple levels of regulation , including gene expression. They show that a large proportion of genes controlled synergistically by loss of function of p53 and Ras activity are critical to the malignant state of murine and human colon cells.
Synergistic control of gene expression by oncogenic mutation is an underlying key to malignancy.
Mind you, this is for colon cells. Maybe other malignancies evolving from other mechanisms behave differently. Time will tell.
McMurray et al 2008, Synergistic response to oncogenic mutations defines gene class critical to cancer phenotype Nature vol 453 pp 1112 = 1115)

Family income and food

In the Financial Times of June 21/ 22 p 6 there is an important article on the effect of rising food and fuel prices on social stability, wherein governments might fall as hungry and fuel deprived people take to the street.
The share of family income spent on food in different countries
USA 10%
Brazil 20%
China 30%
Kenya 50%
Bangladesh 65%

acrylamide formation in food

Foods are thermodynamically unstable and all manner of reactions may take place which may lead to profound changes in the food, sometimes adding to the desirability of the food or creating a hazard. ( British Journal of Nutrition vol 99, supplement 2 April 2008).
The chemical compound acrylamide (acrylic amide) has the chemical formula C3H5NO. Its IUPAC name is 2-propenamide. , for use in wastewater treatment, gel electrophoresis (SDS-PAGE), papermaking, ore processing, and the manufacture of permanent press fabrics. Some acrylamide is used in the manufacture of dyes and the manufacture of other monomers.
Acrylamide was accidentally discovered in foods by scientists in Sweden who found large amounts of the chemical in starchy foods, such as potato chips, French fries and bread that had been heated (production of acrylamide in the heating process was shown to be temperature-dependent
Acrylamide production in food is a consequence of the Maillard reaction between asparagines and reducing sugars
The product is a genotoxic carcinogen. There are two important points here. Such carcinogens have no threshold concentration and there is no data for carcinogenic consequences in man.
The amount of acrylamide formation depends upon the concentration and availability of the precursors in the food. This is affected by variety, growing conditions, time of harvest and storage of the product.
Potatoes, cereals and coffee are the most important sources of acrylamide formations. The reaction depends upon the temperature, heat intensity and water activity .
There is a detailed and definitive review iby Seal et al ( 2008) which describes in detail the complexities of the creation of this unwanted addition to the diet.
Seal et al 2008 Risk –benefit considerations of mitigation measures on acrylamide content of foods- a case study on potatoes, cereals and coffee .British Journal of Nutrition vol 99 suppl 2, ppS1-38

surgery for obesity

Obesity may be difficult to overcome and in these situations the surgeons as always have explored surgical management of the problem.
In the Journal of the Royal College of Physicians of Edinburgh Witherspoon and Galloway review surgical procedures useful for obesity control.
Medical treatment for the grossly obese is not always effective in the long term.
In these situations bariatric surgery has much to offer.
The operations may be
1. restrictive procedures.
reducing the functional capacity of the stomach by reducing the capacity of the stomach with a band across the upper stomach
2 . operations resulting in malabsorption
These reduce the absorptive capacity of the intestine , either by bypassing part of the intestine or removing small bowel.
2. A mix of 1 and 2. Laparoscopic small gastric pouch with bypass of remaining stomach , duodenum and variable length of jejunum.
Weight loss may be very good, 50 to 75 %.
The gastric banding complications are mechanical, band erosion and slippage.
The creation of malabsorption requires very careful follow up as very severe complications may result. Apart from the malnutrition some patients will have disabling diarrhoea and incontinence.
Overall restrictive procedures are the best.
Witherspooon and Galloway 2008 Surgery for severe obesity: an effective cure for a difficult problem J R Coll Physicans Edin vol 38, 129-30

cleaning chemicals and fertility in mice

Nature reports that a scientist , Patricia Hunt has noted that mice in contact with two compounds used in cleaning homes offices and hospitals develop birth defects and reduced fertility. Two chemicals are quaternary ammonium compounds ADBAC (n-alkyl dimethyl benzyl ammonium chloride) and DDAC (didecyl dimethyl ammonium chloride) .
Similarly bisphenol A causes egg defects.
Here is a chance to develop a kind way to remove mice and possible rats from an environment.
Does this have implications for humans.
News ( 2008 ) Lab disinfectant harms mice fertility Nature vol 453, p 964

obesity and biology of insulin resistance

This is a review of the variable effect obesity has on insulin and skeletal muscle glucose transport.
Acquired resistance to the action of insulin to stimulate glucose transport in skeletal muscle is associated with obesity and promotes the development of type 2 diabetes. In skeletal muscle, insulin resistance can result from high levels of circulating fatty acids that disrupt insulin signalling pathways. However, the severity of insulin resistance varies greatly among obese people. The authors suggest that this variability might reflect differences in levels of lipid-droplet proteins that promote the sequestration of fatty acids within adipocytes in the form of triglycerides, thereby lowering exposure of skeletal muscle to the inhibitory effects of fatty acids.
Adilson Guilherme et al (2008 )Adipocyte Adipocyte dysfunctions linking obesity to insulin resistance and type 2 Nature Reviews Molecular Cell Biology 9, 367-377

biology of starvation

The response of the body to starvation is a complex process. This paper is interesting, because if there is loss of ribosomes, then refeeding has to be a cautious process until the cellular synthetic processes are restored to full .
Autophagy is a process in which cytoplasmic components are broken down to supply materials for the synthesis of essential molecules under nutrient-limiting conditions. Because this process involves random sequestration of the cytoplasm by large membrane vesicles, considerable amounts of molecules, such as ribosomes, are necessarily degraded by autophagy. However, starving cells also promote additional selective degradation of ribosomes as a requirement for survival.
Hitoshi Nakatogawa and Yoshinori Ohsumi (2008) Starved cells eat ribosomes Nature Cell Biology vol 10 pp 505-7

Infant growth monitoring

The value of growth monitoring in infants is discussed at length in an important review by Ashworth et al (2008) Maternal & Child Nutrition vol 4 pp 86-117
The rationale for growth monitoring and promotion is almost self evident, but is it?. The concerns are based on low participation rates, poor health worker performance and inadequacies in health systems minimizing what can be done to alleviate the
problem.
The launch of the new World Health Organization growth standard and charts has reopened the debate. Growth monitoring programmes should improve nutritional status, increase utilization of health services and reductions in mortality.
There is evidence from small-scale studies in Nigeria, Jamaica, India, and from large programmes in Tanzania India , Madagascar and Senegal that children whose growth is monitored and whose mothers receive nutrition and health education and have access to basic child health services have a better nutritional status and/or survival than children who do not. There is evidence from India and Bangladesh that growth monitoring has little or no effect on nutritional status in large-scale programmes unless there is good nutrition counselling.
The programme should be
Where possible chart weights at birth, immunization (6, 10, 14 weeks and 9 months), vitamin A distribution and sick-child visits. Follow up and counsel any
Child whose weight is faltering and those with a weight-for-age <-2 SD.
Combine growth monitoring with other health intervention channels such as immunization for the convenience of caregivers, and ensure consistent message delivery. Target younger children and use the time gained to improve services. Monitor weight until 12 months of age. If there are ,episodes of growth faltering, continue to monitor until 18 months. ‘Training, supervision and support will need to be improved if health workers are .to be equipped with the necessary knowledge and communication skills to i promote healthy growth. Impact will be related to coverage, intensity of contact, -health worker performance, adequacy of resources and the ability and motivation of families to follow advice.
c
Ann Ashworth, Roger Shrimpton, Kazi Jamil (2008) Growth monitoring and i promotion: review of evidence of impact Maternal & Child Nutrition 4 (si) , 86-117

Mediterranean diet and type 2 diabetes risk

Many studies have shown that a Mediterranean diet has a role in prevention of cardiovascular disease, and some suggest that it could also protect against diabetes. Protective characteristics include a high intake of fibre, a high intake of vegetable fat, a low intake of trans fatty acids, a moderate intake of alcohol, and the abundant use of virgin olive oil which is rich in monounsaturated fatty acids. Diets rich in monounsaturated fatty acids improve lipid profiles and glycaemic control in diabetics.
Martinez-Gonzalez et al in the BMJ of 14th June 2008 pp 1348-1351 looked at the relationship between adherence to a Mediterranean diet and the incidence of diabetes among initially healthy participants.
The prospective cohort study took into account relative risk adjusted for sex, age, years of university education, total energy intake, body mass index, physical activity, sedentary habits, smoking, family history of diabetes, and personal history of hypertension.
The study was set in a Spanish university department, 13 380 Spanish university graduates without diabetes at baseline were followed up for a median of 4.4 years
Dietary habits were assessed at baseline with a validated 136 item food frequency questionnaire and scored on a nine point index. New cases of diabetes confirmed through medical reports and an additional detailed questionnaire posted to those who self reported a new diagnosis of diabetes by a doctor during follow-up.
Participants who adhered closely to a Mediterranean diet had a lower risk of diabetes. The incidence rate ratios adjusted for sex and age were 0.41 (95% confidence interval 0.19 to 0.87) for those with moderate adherence (score 3-6) and 0.17 (0.04 to 0.75) for those with the highest adherence (score 7-9) compared with those with low adherence (score <3).
They concluded that a Mediterranean diet is associated with a reduced risk of diabetes.
Martinez-Gonzalez et al 2008, Adherence to Mediterranean diet and the risk of developing diabetes: prospective study. BMJ vol 336 pp 1348-1351

Obesity in Swedish Conscripts

There is no doubt that obesity is a real community problem. An elegant study of Swedish Army Conscripts gives further evidence of the change in fitness in a progressive country.
Neovius et al( 2008 ) Shift in the composition of obesity in young adult men in Sweden over a third of a century International Journal of Obesity (2008) vol 32, pp 832–836;
The studied assessed whether there had been a change in the number of young Swedish men classifiable as obese (body mass index (BMI) 30) during the last one-third of a century.
The study was retrospective of 1, 580,913 men (18.3 0.4 years) representing 82% of the Swedish male population at military conscription age between 1969 and 2005. Measured height and weight were used to define moderate and morbid obesity as BMI 30–34.9 and 35, respectively..
From 1969–1974 to 2000–2005, the prevalence of moderate obesity almost quintupled (0.8–3.8% ; P<0.0001), while morbid obesity increased 10-fold (0.1–1.3% ; P<0.0001). The composition of the obese category changed from 12.9 to 25.1% morbidly obese during the same time, corresponding to an annual growth in the odds of 2.8% (CI95% 2.5–3.1% ) per year within the obese category. Compared to 1969–1974, the odds ratios of obesity and morbid obesity, respectively, were 1.6 (1.6–1.7) and 1.9 (1.7–2.2) in 1980–1984, 2.8 (2.7–2.9) and 4.0 (3.5–4.5) in 1990–1994, and 6.0 (5.7–6.3) and 11.4 (10.1–12.9) in 2000–2005, Extrapolation of the growth rate during the observation period resulted in an estimated 4% morbidly obese in 2020.
Morbid obesity increased faster than moderate obesity during the last 35 years.

vitamin D status in Pakistani families in Denmark

This paper Andersen et al ( 2008 ) Pakistani immigrant children and adults in Denmark have severely low vitamin D status Eur J Clin Nutr 62: 625-634
is an important paper in that here is further underlining of th need to monitor the health of immigrants . Especially in this case where the climate is so different to the country of origin. Further more the immigrants may congregate in Cities , live indoors and avoid sun life. The mal effects of sun light deprivation and reduced vitamin D levels are profound.

refeeding complications

This is very important review by Stanga et al on the refeeding of very sick patients. Worsening the problem is not a good stategy.
Stanga et al ( 2008) (2008) Nutrition in clinical practice—the refeeding syndrome: illustrative cases and guidelines for prevention and treatment
European Journal of Clinical Nutrition 62, 687–694;
The Refeeding syndrome is a potentially lethal complication of refeeding in patients who are severely malnourished from whatever cause. Too rapid refeeding, particularly with carbohydrate may precipitate a number of metabolic and pathophysiological complications, which may adversely affect the cardiac, respiratory, haematological, hepatic and neuromuscular systems leading to clinical complications and even death. The authors review the development of the refeeding syndrome in a variety of situations and, from this and the literature, devise guidelines to prevent and treat the condition. They also report seven cases illustrating different aspects of the refeeding syndrome and the measures used to treat it. The specific complications encountered, their physiological mechanisms, identification of patients at risk, and prevention and treatment are discussed. Each case developed one or more of the features of the refeeding syndrome including deficiencies and low plasma levels of potassium, phosphate, magnesium and thiamine combined with salt and water retention. These responded to specific interventions. In most cases, these abnormalities could have been anticipated and prevented. The main features of the refeeding syndrome are described with a protocol to anticipate, prevent and treat the condition in adults.
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cell flexible activity

When I was taught anatomy, we the heirs of the EB Jamieson tradition were left in no doubt that muscles, nerves, arteries and veins occupied fixed positions in the body. Once transplantation became common this was shown not to be the case. There were variables eg two renal arteries.
Similarly biochemistry has been taught as a fixed system. The implication was that the same fundamental processes went on in each cell in the body. It would appear that the biochemistry of cells is much more random than hither too believed.
Pearson The cellular hullabaloo Nature vol 453 pp 150-153
Identical genes in seemingly identical cells do different tasks. This variation becomes more pronounced as the overall organ becomes older.
The two copies of DNA in the cell are constantly changing shape and structure whilst proteins attach and detach. Such proteins may be activating or suppressing activity. Chaos theory in action. A constant tension between randomness and correction. The switching on and off of processes in individual cells in an organ may be very different. The more fluctuations there are the greater need for suppressing or correcting repressor protein activity. Quite a waste of energy. This activity and flexibility of genes is not universal , some genes are rigid in their activity others are very flexible. ..
Perhaps this system which has many options at any one time is very flexible in its response to the environment eg nutrition and metabolism.

Tuberculosis and factors determining severity.

The balance between nature and nurture and the development of disease is complex. Nutrition clearly has a major role in the health of an individual.
However infections are another major factor.
An article in Nature
Kaufmann 2008, Deadly combination Nature vol 453 p 295-6
describes that not only does the genetic make up of the individual dictate vulnerability to tuberculous infection but also the genetic structure of the tubercle strain.
Normally when a tubercle bacteria reaches the lungs as a droplet, the immune mechanism of the lungs removes the infection. If however the tubercle can bypass this response then an infection results. Detection of the pathogen is through recognition receptor TLR-2 on the surface of the macrophages followed by a signalling cascade mediated by the TLR-2 adaptor protein. T cell white cells are involved.
If the tubercle can bypass this process then infection ensues.
Polymorphism is a feature of tuberculosis and hence the threat from infection persists
I have always felt that the ravages of tuberculosis in 19th century Europe have altered the genetic structure of the surviving families. The survivors for whatever reason were different from the population entering the 19th century.
Many factors would affect survival. Overcrowding, awful working conditions, nutrition and sunlight to name but a few.

Chaos theory

One of the best programmes on the BBC is Melvyn Braggs In our Time. Full of knowledge and wisdom. There is also a wonderful newsletter that comes from his broadcast.
This programe on 29th May talks of chaos theory, of great relevance to biology.
Marcus du Sautoy pointed out that probability comes into play when picking numbers for the National Lottery. The sequence of numbers: '1, 2, 3, 4, 5, 6' are just as likely to come up as any other combination of numbers. Numbers are more likely to come up in clusters because randomness likes to cluster things together (so often you will see clusters of things in a random sample); so if you pick say 42 followed by 43 (e.g. consecutive numbers), there may be slightly more chance of winning a prize
Physical systems that are deterministic yet impossible to predict (ie: requiring
probabilistic predictions) is the study of chaotic systems or 'Chaos Theory'. Chaotic systems were not totally random, crazy and unpredictable but actually rather simpler than they might appear. They follow meta rules, structures and patterns that you can observe, extract and use. So in that sense it is deterministic (ie: run it twice under same conditions and the same outcomes will happen) as opposed to random (which by definition means running the same thing under the same conditions
and getting different outcomes).
However, chaotic systems are characterised by something popularly called the butterfly effect - that if a butterfly beats its wings in Rio you get hurricanes in Tokyo.This is better referred to as 'extreme sensitivity to initial conditions'. A small effect early on leads to vast differences later on. To accurately predict the future of a chaotic system, a measurement of what it is doing now (and upon which the prediction is based) must be unbelievably accurate - just as a butterfly's wings can create storms, so a small error in initial measurement can lead to vast errors in predicted outcomes.
And what does this have to do with nutrition. Metabolism is in part chaos theory in action. The food supply chain certainly is. Choice of food and marketing.

Fat cells

Two factors contribute to an increase in fat mass: the number of fat cells and how much fat each of these cells stores (their volume). Spalding and colleagues studied the dynamics of fat-cell number in some 700 adults, both lean and obese, and combined their data with previous observations in children and adolescents.
Irrespective of weight, the number of fat cells seems to rise steadily from birth to the early twenties, but remains constant thereafter. In patients observed before and up to two years after surgical treatments that facilitate weight loss by reducing stomach size, no decrease in fat-cell numbers was detected, although their volume did drop.
Fat cells have a high turnover: new cells are continually being produced to replace their dead predecessors. The average age of a fat cell seems to be about 10 years in both lean and obese individuals, and the number of fat cells as a proportion of all cells remains constant in each weight group. But the total number of new fat cells was higher in obese subjects, suggesting that they are replenishing an existing larger pool.
In lean individuals the fewer fat cells can still store large amounts of fat
Fat people can still reduce the volume, it not the number of their fat cells.
Shadan (2008), What’s your fat allowance? Nature vol 453, p 169
(K.L. Spalding et al .( 2008 ) Nature vol 453 18th May .

Book review, The end of Food, Paul Roberts.

This book discusses a familiar them. That the World cannot sustain increasing numbers. That the food will run out.
The present crisis in fuel is maybe a fore taste. Who knows but this book is worth looking at.
The End of Food
by Paul Roberts
Houghton Mifflin,
Paul Roberts writes "On nearly every level, we are reaching the end of what may one day be called the `golden age' of food. The soaring cost of corn, wheat, rice and other basic grains, the fruit of record-high oil prices, panic hoarding, greedy speculation, climate change, soil degradation, water shortages, natural disasters, and the heavily subsidized rush to convert edible grains into biofuel. The results: malnutrition, mass protests, and disease.
It's not that the world is running short of plants and animals to fill nearly 7 billion bellies. Not yet, anyway.
But the system for distributing the calories required to keep us going is completely out of control. . At one extreme, it provides North Americans with a calorie rich diet, at the other, it denies even a pitifully adequate supply to at least a billion people.”

Cholesterol synthesis control

Cholesterol synthesis is controlled significantly by the hepatic HMG Co A reductase. Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase produces mevalonate, an important intermediate in the synthesis of cholesterol and essential nonsterol isoprenoids. The reductase is subject to a range of forms of feedback control through various mechanisms mediated by sterol and nonsterol end-products of mevalonate metabolism. In an article in Cell Research DeBose-Boyd reviews recent advances on one mechanism for control of reductase, which involves rapid degradation of the enzyme. Accumulation of certain sterols triggers binding of reductase to endoplasmic reticulum (ER) membrane proteins called Insig-1 and Insig-2. Reductase-Insig binding results in recruitment of a membrane-associated ubiquitin ligase called gp78, which initiates ubiquitination of reductase. This ubiquitination is an obligatory reaction for recognition and degradation of reductase from ER membranes by cytosolic 26S proteasomes. Thus, sterol-accelerated degradation of reductase represents an example of how a general cellular process (ER-associated degradation) is used to control an important metabolic pathway (cholesterol synthesis).
DeBose-Boyd (2008 Feedback regulation of cholesterol synthesis: sterol-accelerated ubiquitination and degradation of HMG CoA reductase Cell Research vol 18:609–621

vernalisation and Lysenko

In Melvyn Bragg’s BBC programme In Our Time and News letter ( 5/6/2008 ) he describes how Lysenko, the controversial Russian Agronomist promoted an agricultural technique known as "vernalisation", which can be defined as the subjection of seeds or seedlings to low temperatures in order to hasten plant development and flowering. The word vernalisation comes from the Latin word "vernus", meaning "of the spring". Lysenko was not the first person to discover
this technique, but he was the first to champion it as the sure fire way to improve crop yields in record time. Peasant farmers had been carrying out their own version of vernalisation for generations when they left grain out in a cold barn which served to toughen the seeds.
A young plant given a cold blast will toughen but Lysenko's claim was that
through vernalisation one species of wheat - winter wheat could be
transformed into another - spring wheat. He germinated the winter
wheat and then subjected it to very low temperatures to halt its
growth until it was sown in spring. Lysenko believed that the shock of
the cold would cause the transformation from one species to another,
and produce greater yields. Lysenko believed that the
crucial factor in determining the length of the vegetation period in a
plant was not its genetic constitution, but its interaction with its
environment. This claims meant that wheat could potentially be grown in the barren north where previously the temperature had proved detrimental to agricultural development .
This was all before Molecular Biology transformed our thinking.
This theory came when the Ukraine and other areas were staving due to collectivisation. Lysenko was taken up at a time when millions were dying in the Ukraine from starvation. It was a desperate, desperate situation and he seemed to be offering solutions.