The Role of Sustainable Fisheries and Aquaculture for Food Security and Nutrition
Comment by Professor Michael A. Crawford PhD, FSB. FRCPath., Imperial College on:
7. How sustainable aquaculture can be promoted for food security and nutrition, as well as livelihoods, into the longer term?
How do we facilitate the development of integrated policies and management measures, which are effective and acceptable to both national and regional administrators?
9. What would promote fish value chain development that supports food security and nutrition?
SUMMARY:
I wish to comment on the above two points. The promotion of sustainable aquaculture is unlikely to be enough to meet equable, nutritional demands of the present and future population. The wild catch reached a limit about 20 years ago. There is therefore a limit to the by-products from the wild catch to meet an ever growing demand from aquaculture. In my view it is unlikely that the need will be made up by land products for 3 reasons (i) the depletion of trace elements in land based agricultural products (ii) the inappropriate fats derived from land products (iii) the limiting agricultural land for products for direct human consumption.
Regarding the second point, the value of marine and even fresh water foods lies not in protein as so commonly perceived. The nutritional value in sea foods and fish is the health giving properties: specifically in the brain specific nutrients and cardio-protection. This property is from the marine fats, especially DHA and trace elements. Protein can be obtained from many sources but the fats and elements cannot. Once this fact is recognised there is a different but large potential for the promotion of the aquaculture and sea foods.
Rationale dictated by population growth:
Global population was 1 billion in 1804. It took 123 years to reach 2 billion in 1927 and another 33 years to reach 3 billion in 1960s. By 2000 it reached 6 billion and it then took only 11 years to add another billion. Although increased wealth is usually associated with reduction in population growth, change will do little in the immediate future. The population growth is exponential and the next 20 years is built on the previous accumulation of people with 8 billion in 7 to 8 years’ time and then 9 billion in sight.
Today, there are 925 million undernourished people in the world. That means 1 in 7 people do not get enough food to be healthy and lead an active life. Hunger and malnutrition are a high ranking risk to the health worldwide — greater than AIDS, malaria and tuberculosis combined (UNICEF). Some 2 billion are malnourished and or suffering from nutrient deficiencies especially iodine. The iodine deficiency is likely to include other trace elements and DHA which co-exist with the iodine and trace element, rich sources in sea foods. Some 600,000 children died last year in Africa from malnutrition
The already stretched food and fresh water resources presents a major global challenge. The arable land mass of the planet is reaching full occupation and there is not enough to meet the nutritional requirements, in an equitable manner for all. This is certainly true when you consider the brain specific nutrients as limiting (specific essential fats and trace elements).
A new contribution by marine agriculture:
Sir John Beddington the UK Government’s Chief Scientist commenting on the Foresight 2011 report on the future of food and agriculture claimed that with the limiting land agricultural land, the challenge can only be met by intensification of agriculture and genetic modification. However, there is an additional answer so far not been considered: marine agriculture. Just as you have grass pasture for cattle and sheep on land so you can have marine grass pasture for fish as demonstrated in Okoyama, Japan or for kelp and direct human consumption as in Indoneisa. Artificial reefs can extend surface area to augment primary productivity and so enhance micro-flora and fauna and hence fish and sea food production using only sunlight and the natural elemental wealth of the marine habitat.
The rise in mental ill-health: The missed significance of brain specific and cardio-protective marine fats.
A point missed by Foresight and the report accompanying this call is that the most serious malnourishment today is responsible for the rise in mental ill-health and disorders of the brain.
This is because both the Foresight and your report cite protein as the prime need. I put it to you that this is a false and misleading point of view based on the historical perspective of protein for growth. This meant protein for body growth. Protein can be obtained from a mired of sources, even grass as exemplified by the high velocity of body growth of cattle and horses. Brain growth is hat is important to H. sapiens.
The prime consideration in humans is the brain which develops on embryonic and fetal life with significant additional formation during lactation. It is noteworthy that human milk has the least amount of protein of any large mammal but more that 10 times the amount of brain specific lipids to cow’s milk. The brain cells are largely made of fat rich in essential fats with docosahexaenoic acid (DHA) being the most critical in signalling systems and limiting in the present diet. It is sparsely available from the land based food web. The richest sources by far are in the marine food web consistent with the fact that the first neural signalling systems and brain evolved 500-600 million years ago used DHA for signal transduction and building the first photon receptors, nervous systems and brains. The same is true for the brain today.
In 1972 there was enough evidence for us to predict that unless the food paradigm changed from protein and body growth to serve the special fatty needs of the brain, then the brain would be next. This prediction has been vindicated.
In 2004 the EU carried out an audit of the cost of ill-health. Brain disorders were found to have overtaken all other burdens of ill health at a cost of €386 billion. A review in 2010 put the cost at €789 billion.
Dr Jo Nurse at the DoH estimated the UK cost of mental ill-health in 2007 at £77 billion – a cost greater than heart disease and cancer combined. Her re-assessment in 2010 found the cost to be £105 billion.
The Global Forum for Health predicts mental ill-health will be in the top 3 burdens of ill-health world-wide in less than 8 years’ time which it will share with heart disease and adverse pregnancy outcomes. Although these have multiple factor causation, there can be little doubt from the historical, epidemiological, experimental and clinical trial evidence that they share adverse nutritional conditions as a primary cause.
The requirement for omega 3 DHA mental and heart health.
There is now ample evidence on the essentiality of DHA for the brain and heart as confirmed by 3 FAO-WHO joint international consultations (1978, 1994 and 2010). The latter consultation concluded that there was a requirement for 200mg/day of DHA during pregnancy to for prenatal brain development and maternal health. The American Heart Association recommends 500mg/day to prevent sudden death from heart disease.
BASED ON 200g/day OF FISH TO PROVIDE 1G OF DHA (OR EPA+DHA)
World Population
Requirement for omega 3
Ammount of fish needed
7 billion in 2010
Population need based on FAO-WHO requirement for pregnancy @ 200 mg/day.
102 m metric tonnes/year.
Population of 9 billion in 2030
Based on pregnancy @ 200 mg/day.
131 m. metric tonnes/year.
Population of 7 billion
Cardio-protective @ 500 mg/day.
255 m. metric tonnes/year.
Population of 9 billion
Cardio-protective @ 500 mg/day.
327.8 m. metric tonnes/year.
Worst case of 7 billion
General health @ 50g/day.
25.5 m. metric tonnes/year.
Worst case of 9 billion
General health @ 50g/day.
32.8 m. metric tonnes/year.
NOTE: There are varying estimates of requirements for EPA and DHA. The requirement is influenced by the omega 6 linoleic acid which has entered the food chain in large amount of since 1950. As omega 6 competes with omega 3, populations with a current low omega 6 intake could benefit from a requirement that is much lower than is common in many industrialised countries. However, to maintain this benefit would require strategic food policy decisions based on enhancing the brain specific nutrient efficacy. At the moment however, the calculations above imply that the present and future situation falls short of meeting global requirements for all for optimal brain development which could explain the rise in brain disorders.
The wild catch was about 104 m metric tonnes in 2005 which with aquaculture takes the total to about 140 m metric tonnes. Currently the Japanese, South Koreans and coastal far Eastern populations meet the 500mg/day and notably have less heart disease and less major depression. However, in many countries, nearly a third of the catch is used for animal feeds. This situation is considered to be a major cause of the extraordinary rise in mental ill-health and other disorders of the brain.
In addition there are trace element requirements which interface with DHA in neural development. Iodine is the most commonly known but selenium, zinc, copper and manganese are also vital for proper brain development and function. Iodine deficiency is the best known to cripple brain and cognitive development. There are currently 2 billion people at risk to iodine deficiency today. It is no coincidence that iodine and the rest are at their richest in the marine food web where they co-exist with DHA. From evidence in the Sudan, it is likely that these iodine deficient populations are deficient of DHA and other trace elements. Such populations often have a high incidence of low birthweight, preterm deliveries and a high peri-natal mortality. Such adverse pregnancy outcome is a risk factor for poor learning and chronic ill health amongst the survivors.
There is an argument that the plant alpha-linolenic acid which is a precursor for EPA and DHA would solve the problem as many vegetarian populations thrive without fish and sea foods. It has been established that the conversion rate in humans is very low. It is likely that the vegetarian populations have adapted to increase efficiency but that will not be true for other populations. However, the vegetarian populations are mostly inland and are at risk to iodine deficiency disorder and hence are likely to be also deficient of DHA and possibly other trace elements such as selenium. Iodine deficiency disorder is rarely found in the neighbouring fishing villages! Additionally as commented by Gopalan at his meeting on nutrition and the brain in New Delhi these same populations have a high incidence of low birthweight and preterm deliveries with impact on learning abilities. This is a controversial and emotional issue. The Darwinian view of natural selection offers the insight to the advantage of preformed DHA (and EPA) a point illustrated by the epidemiology of fish eating population compared to others together with the experimental and trial evidence. In addition of course there is also the trace element requirement which would need to be considered.
In any event to meet the requirement from land products would need the capture of vast quantities of new arable land which is simply not available. Agricultural land is in competition by housing and other development. In the UK for example nearly 70% of the land is used by agriculture i.e. 18,283,000 hectares in 2011 (about 409,000 less than the 18,692,000 in 2007). The length of the coast line is 19,491 miles. Only a tiny proportion is used for oysters and cockles and the like. Whist just like the land, not all could be used for marine agriculture, it is plausible that marine agriculture for the estuaries and shallows with deeper water kelp forests and artificial reefs as in Okoyama, could go a long way to making the UK self-sufficient.
The future is in marine agriculture:
Fresh water fish ponds, in which China is a world leader, can be developed to provide fish which interestingly, can be useful as a source of omega 3 and DHA and trace elements. The point being that the origin of DHA is in solar energy, water plants and algae and the movement of trace elements is from land to rivers and then the sea.
However, the main solution which needs to be considered is marine agriculture as opposed to aquaculture. The aquaculture to which I refer is the feeding of fish in a tank or other enclosure. Marine agriculture as mentioned above, uses solar energy for primary production on which sea foods and fish thrive. The development of the coasts and oceans for food which would be rich in both iodine other trace elements and DHA. These are nutritional elements were involved with the evolution of the brain 500-600 million years ago and the requirement for brain growth, development and health today is still the same. To achieve both successful marine aquaculture and agriculture will require turning back the clock on pollution of rivers estuaries and coast lines. This point was made in the Declaration of Manila 2012. Singapore for example stated that 80% of the pollution of its waters comes from human activity the land.
Michael Crawford 4th April 2013.
Michael Crawford