Hydroponic vegetables: Are they healthy?

This letter was written in response to a study by Ngee Ann Polytechnic researchers which found that many people preferred the taste of hydroponically-grown vegetables over regular vegetables.

Wide appeal

It is easy to understand why "Hydroponic greens win blind taste test" (ST, Feb 16).

Most people do not like vegetables to begin with. They do not like the "green", bitter taste, or the fibrous texture. So, they naturally prefer hydroponic vegetables that are sweeter, more tender, and not quite like the real thing.

But the fact that hydroponic vegetables have wider appeal does not mean that they are "good" and that we should encourage more Singaporeans to consume them.

More people prefer food that contains excessive amounts of salt, sugar and fat. Do a blind taste test on sharks' fin soup and you will find that more prefer the soup prepared with generous amounts of MSG.

Should we, then, encourage people to eat more salt, sugar, fat and MSG? Of course not! There is also the question of long-term health effects.

Most of the newspaper reports on hydroponic vegetables focus on the taste and how productive the method is. I have been following this subject for many years and I can recall only one report (a few years back) which talked about their nutritional value.

Yet that report discussed only Vitamin C, potassium and a few other nutrients. What about all the other nutrients that contribute to health? What about the fibre content, which is one of the major benefits of eating vegetables?

Will the Singapore Polytechnic researchers and health authorities, such as the Health Ministry and Primary Production Department, tell consumers:

Have there been any nutritional studies on hydroponic vegetables which examined a broad range of nutrients?
Have there been any studies on the long-term health effects of eating hydroponic greens? For example, studies where laboratory animals fed with them were then exposed to bacteria and viruses to test their immune responses?

I raise this issue because I know of studies that showed that eating organic vegetables -- grown naturally in soil, without chemical fertilisers and without pesticides -- boosted the immune system of animals and helped them recover from disease.

It was found that bacteria and fungi in the soil passed their immune factors to the vegetables, which, in turn, passed them on to the animals that ate them.

Hydroponic vegetables are grown in a totally unnatural way, without soil, in a solution of chemical nutrients but, thankfully, still without pesticides. Since they are almost the exact opposite of organic vegetables, it is logical to conclude that their health effects might also be the exact opposite.

Taking an even longer term view, have there been studies where laboratory animals are fed hydroponic vegetables for a few generations to find out whether subsequent generations turn out to be healthier or more sickly?

These, rather than taste, are important questions that must be examined.

The Ngee Ann Polytechnic researchers have set a goal for 40 per cent of the vegetables consumed here to be hydroponic within a few years.

My goal, as a teacher of natural health, is to have Singaporeans eat 100 per cent organic vegetables.

Published in The Straits Times
18 February 1999

Misgivings about Hydroponics

Below is a follow-up letter in response to replies from the Ngee Ann Polytechnic and the Primary Prduction Department, and to a newspaper reader who argued that pesticides in vegetables are a bigger worry.

I agree with Mr Wong Yew Kwan that pesticides in vegetables are a bigger worry
(ST, March 4). Hydroponic vegetables, being pesticide-free, are safe -- you will not drop dead from eating them.

My misgivings are not about immediate safety, but about the long-term health effects of eating hydroponic or aeroponic vegetables.

There are many reasons to believe that long-term consumption of such unnatural foods will weaken us. For one thing, the seeds of hydroponic vegetables cannot be used to plant beyond the next one or two generations of crops. Hydroponic vegetables are, therefore, infertile.

From the theoretical perspective, Mr Wong and other advocates of unnatural agriculture can argue that plants absorb nutrients only after they have been broken down into their basic components, and so there is no difference whether those nutrients come from manure, compost or factory-made chemicals.

But there is a big difference between vegetables grown in soil using chemical fertilisers and those grown in soil using natural fertilisers such as manure and compost. It is, therefore, logical to suspect an even bigger difference when vegetables are grown without soil.

In my original letter, I asked:

Have there been any nutritional studies done on hydroponic vegetables which examined a broad range of nutrients?
Have there been any studies done on the long-term health effects of eating hydroponic vegetables? For example, studies where laboratory animals were fed hydroponic vegetables and then exposed to bacteria and viruses to test their immune response?
Have there been studies where laboratory animals were fed hydroponic vegetables for a few generations to find out whether subsequent generations turned out to be healthier or more sickly?

Both the Primary Production Department (PPD) and Ngee Ann Polytechnic failed to mention whether a broad range of nutrients had been studied.

And since they kept silent about long-term animal studies, I take it that no such studies have been done.

Published in The Straits Times
5 March 1999