Even more vegetables

fruitandveg

We should eat more fruit and vegetables

The World Health Organisation advised in 1990 that the minimum daily intake of fruit and vegetables should be 400 g a day, but note that this excludes consumption of potatoes and other starchy tubers. The aim was to prevent chronic diseases such as heart disease, cancer, diabetes and obesity, and to reduce several micronutrient deficiencies, especially in less developed countries.  To promote the recommendations, WHO and FAO started a joint worldwide initiative in 2003.

But what exactly we should eat is not so easy. The definition of the word vegetable is somewhat arbitrary and subjective. All parts of herbaceous plants eaten as food by humans are normally considered vegetables. Mushrooms, actually belonging to the biological kingdom fungi, are also commonly considered vegetables. Potatoes and other starchy tubers are included in the definition of vegetables in some countries but not in others, which is not that helpful. Nuts, grains, herbs, spices and culinary fruits are normally not considered as vegetables. Botanically, fruits are reproductive organs, while vegetables are vegetative organs which sustain the plant. Nevertheless, several fruits, e.g. cucumbers and tomatoes, are also included in the term vegetables.

Confused?

A formal definition of fruits and vegetables by the World Health Organisation might help:

Fruit and vegetables are edible plant foods excluding cereal grains, nuts, seeds, tea leaves, coffee beans, cocoa beans, herbs and spices.

Fruits are edible parts of plants that contain the seeds and pulpy surrounding tissue; have a sweet or tart taste; generally consumed as breakfast beverages, breakfast and lunch side-dishes, snacks or desserts.

Vegetables are edible plant parts including stems and stalks, roots, tubers, bulbs, leaves, flowers, and fruits; usually include seaweed and sweet corn; may or may not include pulses or mushrooms; generally consumed raw or cooked with a main dish, in a mixed dish, as an appetiser, or in a salad.

Are you with me so far?

Now some countries have attempted to translate this into portions to help your calculations.

In the United Kingdom the recommendation is to eat five fruit and vegetable portions a day with each portion equivalent to 80 g. However, only about 30% of the population manage to consume the recommended amount.

Australia went one step further and recommends two fruit and five to six vegetable portions a day with the fruit portion at 150 g and vegetable portion at 75 g. This equates to an enormous total of 675 to 750 g. Quite an ambitious target. Close to 50% of Australians reported that they usually ate two or more serves of fruit per day, while 8% usually ate five or more serves of vegetables per day. Taking both guidelines into account, only 5.5% of Australian adults had an adequate usual daily intake of fruit and vegetables.

Canada previously recommended five to ten portions for all, but changed this in 2007 to specific recommendations for each age and sex group. They now recommend a minimum of four portions for young children up to a minimum of eight portions for adult males. Only 26% of the population aged 2 years and older consumed the minimum number of daily servings recommended for their respective age–sex group.

France and Germany also recommend five portions a day while portion numbers vary in other European countries. The United States abandoned the numbers in favour of a generic fruit and vegetable campaign in 2007 indicating that the more you eat the better it is. In Europe, the average consumption of fruit and vegetables is only 220 g per person per day and just 27% of European mothers consume over 400 g. The French did not reach the recommended amounts consuming fruit only 1.3 times per day and vegetables 2.3 times per day despite all the talk about the beneficial Mediterranean diet. Still this was better than the Americans. Adults in the United States consume fruit about 1.1 times per day and vegetables about 1.6 times per day. That is definitely on the low side but not breaking any non-existent recommendations.

Given our notorious dishonesty when confronted by pollsters with questions that touch on our self-regard, there might even be a lot less five-a-day eaters than indicated above.

But if you are struggling with reaching the current recommendations just wait for it.

A new study, carried out by researchers at University College London, analysed information from more than 65,000 adults aged 35 years or older, who responded to the Health Survey for England. Researchers then followed up participants for an average of 7.7 years after their initial participation. The study found that people who ate seven or more portions of fruit or vegetables a day had a 33% reduced risk of death from any cause, a 25% reduced risk of death from cancer and a 31% reduced risk of death from cardiovascular disease, compared with people who ate less than one portion per day.

Not even 400 g is enough

Not even 400 g is enough (Chris Walton)

So not even five portions of fruit and vegetables a day may, after all, be enough. There was a surprise finding – eating canned or frozen fruit actually may not be helpful at all. This is a little confusing but it could be that people eating canned fruit may not live in areas where there is fresh fruit in the shops, which could indicate a poorer diet. And merging canned and frozen fruit might not be fair to the frozen produce.

The clear finding was that eating more fresh fruit and vegetables, including salads, was linked to living a longer life generally and in particular, to a lower chance of death from heart disease, stroke and cancer. Vegetables seemed to be significantly more protection against disease than eating fruit.

The researchers commended the Australian example as the one to follow where the balance is two fruit and five vegetables. That is if the reduced risk of disease is entirely attributable to fruit and vegetable consumption, or they are acting as a marker of a broader dietary pattern associated with improved health.

Your call, but to up your fruit and vegetable consumption to close to 800 g a day might not be easy.

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Beware of trans fats

No question about it. Trans fats are bad for us. Something we have known for quite some time, but not been doing that much about. Food authorities in many countries have issued warnings but hoped for voluntary action by the food industry to reduce the trans fat in their products. To a part this has also happened but not enough has been done. It is believed that current intake remains a public health concern.

A few countries, the first being Denmark, did ban trans fats, but now there is a further call for action. The Food and Drug Administration (FDA) in the USA has finally started to move by issuing a preliminary determination that partially hydrogenated oils are no longer GRAS.  That is they are not generally recognised as safe (GRAS) and will require premarket approval should the preliminary determination be finalised. This could start a ripple effect in many other countries.

So what are we talking about?

Subtle changes in fat structure - trans to the left and cis to the right (Photo: Wikimedia)

Subtle changes in fat structure – trans to the left and cis to the right (Photo: Wikimedia)

Trans fats are formed when vegetable oils are treated with hydrogen, changing their chemical composition. This process allows the liquid oil to remain solid at room temperature, preventing biscuits and cakes from going soggy and extending their shelf life. In chemical terms, trans fat is a fat molecule that contains one or more double bonds in trans geometric configuration. A double bond may exist in one of two possible configurations: trans or cis. In trans configuration, the carbon chain extends from opposite sides of the double bond, whereas, in cis configuration, the carbon chain extends from the same side of the double bond. The trans molecule is a straighter molecule. The cis molecule is bent.

The cis configuration is the natural form of unsaturated fatty acids. The process of hydrogenation adds hydrogen atoms to unsaturated fats, eliminating double bonds and making them into partially or completely saturated fats. Typical commercial hydrogenation is partial in order to obtain a mixture of fats that is solid at room temperature, but melts upon baking or consumption to make the food product taste that special extra. And in here lies the problem. Partial hydrogenation converts some of the cis configuration into trans-unsaturated fats instead of hydrogenating them completely.

And to the damage of trans fats

Sorry for the complex background but to understand the issue it is important to know what we are talking about. With the chemistry out of the way it is time to look at the bad effects of trans fats.

Various studies have over some time now linked trans fats to heart disease. A 2002 report by the National Academy of Science’s Institute of Medicine in the USA found a direct correlation between intake of trans fat and increased levels of low density lipoprotein (LDL) cholesterol, commonly referred to as “bad” cholesterol, and, therefore, increased risk of heart disease. And as if this was not enough, trans fats also lowers the levels of the high density lipoprotein (HDL) cholesterol, the so called “good” cholesterol that you actually want.

The Centers for Disease Control and Prevention in the USA estimates that a further reduction of trans fat in the food supply can prevent an additional 7,000 deaths from heart disease and up to 20,000 heart attacks each year in the American population. It is also expected that rates of diabetes, obesity, and some other ailments might be reduced as well.

Where can we find the trans fats?

Donuts (or doughnuts) often culprits with trans fat (Photo: Eric Herot)

Donuts (or doughnuts) often culprits with trans fat (Photo: Eric Herot)

More than a decade ago with the initial trans fat debate consumers started to avoid foods with trans fat and companies responded by reducing the amount of trans fat in their products. However, there are still many processed foods made with partially hydrogenated oils, the major dietary source of trans fat in processed food. Trans fat can still be found in such processed foods as crackers, cookies, cakes, frozen pies and other baked goods. Certain products such as microwave popcorn, shelf stable cakes and donuts are likely to have a higher content. It can also be found in chicken nuggets, frozen pizza, coffee creamers and vegetable shortenings.

Actually, some trans fats can be found naturally at low levels in meat and dairy products. Natural trans fats, which include conjugated linoleic acid and vaccenic acid, originate in the rumen of cattle and sheep and can comprise 2–5% of total milk and body fat. There is still debate about the harmfulness of such natural trans fats but the most convincing evidence points to their inclusion on the harmful side.

What can you do?

In waiting for further action from food authorities and the the industry there are a few things you can do. If there is compulsory label requirements you should look out for any trans fat levels declared. If not it could pay off to look at partially hydrogenated oils in the ingredient list. Thing is that products containing less than 0.5 grams of trans fats might in many circumstances be rounded down to zero. But if there is partially hydrogenated oil listed with the ingredients, there might be a small amount of trans fat. Selecting foods with even small amounts of trans fat can add up to a significant intake.

So be careful in your food choice and don’t eat donuts or microwave popcorn too often.

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