Tag Archives: nutrition

nutrition & flavour: a little hardship helps

There have been suggestions in the media that the very wet, dull weather in 2012 has reduced the nutritional value, flavour and yields of vegetables. Some have postulated that organic crops, un-bolstered by agrochemicals, might be more severely affected.

When rainfall exceeds the sum of moisture lost through evaporation (from the surface), transpiration (from plants) and the sponge-like ability of the top soil to absorb water, the excess will percolate through the soil, taking anything soluble with it. Highly soluble nitrogen is lost to the subsoil (out of the rooting zone of most vegetable crops) and eventually pollutes watercourses. Conventional farmers can replace it by adding relatively cheap (hugely carbon intensive), synthetic ammonium nitrate. Organic farmers have to wait for the soil fungi and bacteria to break down complex organic matter to the smaller, soluble nutrients available to plants. Part of the skill of organic farming is balancing the natural release of nutrients with the needs of the crop; we base our plans on an average year, not 2012. Hence it’s fair to say that organic farmers have suffered more in terms of yield this year. Pouring on nitrogen may mitigate yield loss but does not compensate for lack of sunshine and other nutrients and tends to dilute nutrition and flavour.

A little hardship is generally no bad thing. Slower growth can help plants develop their full flavour and improve nutrient content. Some disease fighting chemicals are actually produced as a response to stress or threat. There is often a negative correlation between yield, flavour and nutrient content: the ‘dilution effect’ (the nutritional value of vegetables has fallen by about a third since the adoption of chemical farming in the 1960s). Sunshine is essential, as plants use it to produce sugars. We found flavour a bit dull in the sun-loving lettuce, tomatoes, strawberries and some apples, all of which would prefer to be further south. Cabbage, sprouts, spinach and leeks are happier at our latitude and have been fine. Surprisingly our radicchio was the sweetest I have known.

Guy Watson

The which? report

You may have read that consumer group Which? has suggested that there appears to be little or no nutritional or taste benefits to growing food organically.

It is very hard to make a sensible comment without knowing how the vegetables were grown, the size of the trial or whether it was replicated as would normally be expected. I would never claim that being organic necessarily guarantees better flavour or nutritional quality. In our experience, flavour and (probably) nutritional quality are a result of:

1. variety

2. soil type

3. growing conditions

4. stage of ripeness or maturity at harvest

5. freshness (time from harvest and post harvest treatment)

I can’t speak for our other growers, but at Riverford we work hard to combine all these factors to give the best flavour. A poor variety grown quickly on Fenland peat with excessive nitrogen can be organic but it can also be disappointing to eat.

On the whole organic growers tend to be more interested in getting these things right, so organic veg is usually better; but it doesn’t have to be. There are of course many other reasons for buying organic, including environmental, animal welfare and absence of pesticide residues.

Guy Watson

Food Standards Agency report on organic food – customer response

Contrary to most of the press coverage, the Food Standards Agency report published last week did not prove that organic food was no better for you than non-organic. It merely showed that there was no conclusive evidence either way, on the grounds of a limited review of existing research into a limited range of nutrients taken in isolation.

A customer’s thoughts
Thankfully many of our customers read past the headlines. Diane sent us this email in response to the FSA report:

“Firstly I would like to thank you for todays box of fresh, tasty, reasonably priced, nutritious vegetables, grown with conscience and compassion and most importantly without man-made chemicals.

I have just read the accompanying newsletter entitled ‘misguided?’ and I thought perhaps a ‘customer’ reaction to the FSA’s report might be gratifying for potentially damaged morale.  I personally found the well publicised conclusion of the report somewhat incredulous; how can such a statement be made when only a number of nutrients have been considered and no other aspect of production has been taken into account.  Additionally, does this statement truly reflect analysis that shows a positive increase in a number of important nutrients but which appears to have been ignored on the basis that there are too few studies to take the data from.  During the last week it has become very apparent to me that many people simply scan read the newspaper primarily noting the headlines, no doubt as a result of our busy lives.  Such statements/headlines are therefore often taken out of context with potentially damaging results.  Perhaps we need to consider who stands to gain from such statements; are the interests of the global chemical giants being protected here? One would hope not but it is a worrying thought.

Keep up the good work Riverford, we still love you despite what you may read in the papers!”

What works for you?

From September we will have to feed the contents of the meals we cook for our local school into a computer which will tot up the nutrients and tell our cook if they are fit to eat. I am sure this initiative is full of good intentions, and may even help to reduce some abuses at the lower end of school catering, but it strikes me as depressingly reductionist, culturally degrading and an intrinsically unhealthy approach to food.

In a recent edition of Radio Four’s excellent Food Program, Michael Pollan author of “In Defence of Food”, gave some simple guidance on how to eat a healthy diet and enjoy it:

1. don’t eat anything your great grandmother would not recognise as food
2. don’t buy anything with more than five ingredients
3. only eat at a table; eat slowly and communally
4. distrust any food claiming health benefits

This all made so much sense that I bought the book, the gist being that your granny is a better source of dietary guidance than science and nutrition experts. Having spent five years studying natural sciences I am wary of unquestioning adulation of native wisdom but when it comes to nutrition, science has earned a bad name. Our relationship with food is far more complex than simply summing up the known,nutrients and multiplying by their known effects on our bodies – there is just too much that we do not know. Judging from a recent article in the New Scientist we are still far from understanding the relationship of appetite, diet and weight gain but this has not prevented the proliferation of highly processed functional foods marketed on their ability to fight coronary heart disease and help weight loss.

Science will not solve a cultural problem; namely a collapse in the willingness, confidence and skills needed to cook and enjoy real food. There is no one healthy diet, no silver bullet that can better the knowledge, accumulated over generations, of how to use predominantly locally sourced ingredients to sustain us through happy and healthy lives. Pollan’s advice is, that unless you suffer from a specific illness like diabetes, the best thing to do with a nutritionist’s advice is to ignore it.

Guy Watson

Organic tomatoes better for your heart

Reported in The Times* and The Telegraph* today are the results of a 10-year study comparing organic tomatoes with rival produce suggests they have almost double the amount of antioxidants called flavonoids that protect the heart. According to the findings, levels of quercetin and kaempferol were found to be on average 79 per cent and 97 per cent higher, respectively, in organic tomatoes.

Peter Melchett, Soil Association policy director, is quoted in The Times, “We welcome the now rapidly growing body of evidence which shows significant differences between the nutritional composition of organic and non-organic food. As further scientific evidence emerges from new research looking at differences between organic and non-organic food, the Soil Association will be asking the FSA to keep their nutritional advice to consumers under review.”

*please note: as this is an older blog post, some of the original links in this article have been changed or removed