Looking for more evidence for veggie benefits (above supplements)

Two-and-a-half years ago, I posted this thread to this forum:

What EVIDENCE is there that vegetables > vitamin pills?

In that thread, I posted a link to a webpage of mine titled Vegetable-Free Living, which was a sometimes-serious, sometimes-ranting, sometimes-tongue-in-cheek screed against the notion that vegetables are necessary for health.

Well, recently, some evidence was (finally!) presented to me which showed health effects gained from eating vegetables that could not be gained by getting the same vitamins, minerals, and fiber from other sources. But to my eye, this evidence seemed … not all that strong. Vegetables may protect against cardiovascular disease, as revealed by the Nurses’ Health Study. Vegetables seem to reduce the incidence of certain kinds of cancer, but not others (and colon cancer was not among the kinds of cancer that vegetables prevent). Mechanisms have been suggested as to how the health benefits of the non-vitamin, non-fiber phytochemicals in vegetables might work. And vegetables are one of the tools available in weight loss for combatting obesity.

I incorporated that evidence into Chapter 1 of my screed here:

But the basic message of this chapter remains unchanged. Its basic message is this:

There is insufficient evidence that vegetables are necessary for healthy living, provided you get enough vitamins, minerals, and fiber from other sources.

What I’m on here asking for is, basically, more evidence in favor of vegetables.
I’m looking for studies demonstrating that vegetables are necessary for healthy living, even if you get enough vitamins, minerals, and fiber from other sources. I want you to prove me wrong. In the words of Ellie Arroway from the movie Contact, “Make me a liar!”.

It sounds like you are basically suggesting a perfect artificial diet or some strange unbalanced diet like an all meat and cheese menu. It can be done even even done well as long as you have the resources and medical monitoring to ensure you remain healthy and make adjustments as needed.

My objection to your statement is mainly regarding the fiber comments. Fiber appears to be much more critical to overall health and maintaining a healthy weight than previously believed. All of the common fiber supplements that I am aware of are plant and vegetable derived so it sounds like a cheat to just wave that away. Just because you can get fiber in a pill or mix it with water doesn’t mean that you aren’t consuming vegetables. Processed vegetables or their components are just more expensive versions of the original to me at least.

The biggest downside to maintaining a radically unconventional diet is keeping everything at safe and healthy levels. It happens naturally for healthy people that maintain a truly varied and sensible diet but things become complicated once you start removing whole categories of food types and replacing them with supplements. It isn’t difficult to replace vitamins and minerals with supplements. In fact, it is fairly easy to get too much of them that way even if the long-term risks of that aren’t clear in most cases.

What is truly difficult is maintaining healthy gastrointestinal flora when you deviate away from a more traditional diet. That appears to be a cause (if not the major cause) to many health issues that are springing up at an alarming rate in the general population in conditions ranging from diabetes to obesity and proper even some mental health conditions and many more. Junk food and all heavily processed foods are another type of supplement after all. The disadvantages of eating too many of those are profound and obvious.

You need to read up on the role of GI flora (those are your gut bacteria). There is volumes of research on that and more is coming every day. That appears to be the flaw in your line of reasoning.

Ah, I think you misunderstand my objective. The goal here isn’t so much “avoid anything made out of vegetables”, it’s “have a diet that doesn’t include any vegetables in their intact, ‘icky vegetable’ state if you don’t like to eat vegetables.”

If an entire serving of (say) broccoli could be squeezed down into a single easy-to-swallow capsule, that would suffice. But unfortunately, doing so is not possible, as far as I know.

‘Vegetable’ is a culinary rather than a scientific term. Do you really want to avoid eating all fruits and vegetables or just things like broccoli? You don’t have to eat broccoli, Brussels sprouts, cauliflower or kale if you don’t want to and you can still be perfectly healthy. Those are all cultivars of the same plant species, brassica oleracea, believe it or not and many people hate some or all of them.

Can you live with things like watermelon, sweet potatoes and healthy grains as a few examples? If so, you you don’t need the full spectrum of all vegetables to be healthy. Those also have everything you need when combined in appropriate proportions. That doesn’t even require any supplements at all, just basic menu planning.

I have my own food preferences, but I’m actually more interested in the broader picture of a “generic” vegetable-free diet.

Specificall: A diet that does not include anything on the USDA’s vegetable food group that isn’t also in another USDA food group.

Note that there are a couple of items in that Food Group that also appear in other food groups. Corn and potatoes, for example, appears in the Vegetable Food Group as “starchy vegetables” – however, they also both appear in the grain group in the form of popcorn and potato bread. So they would be allowed, provided they’re in their “grain” form. Similarly, soybeans appear in the Vegetable Food Group as “beans”, but they also appear in the Protein Food Group as tofu and in the Oils Food Group as soybean oil, so they would also be allowed.

So you understand and accept the evidence that supplemental vitamins do not provide the same benefits reducing stroke, heart disease, and many forms of cancer risk that are associated with a diet high in vegetables and fruits?

Was it the fruit? Or the fiber? Or the phytochemicals in the vegetables? Or something about the complete package? Other? The study cannot say. What it can conclusively say is that vitamin supplements don’t do it. Fiber alone has benefits but not all of them plus 1) fiber supplements tend to have a more limited variety of sorts of fiber 2) taking fiber supplements to reach the levels met by diets high in vegetables and fruits is pretty unpalatable for most people, 10 tablespoons or 60 capsules a day.

Is it possible that some reductionist approach will identify the individual bits and package them in some pill? Maybe. But for now the only package proven to have the benefits of a diet high in vegetables and fruits and whole grains has been a diet high in vegetables and fruits and whole grains.

But as you define your goal? Sure, sweet potatoes, legumes, etc. can all be found as flours and cooked into breads or even pureed in. Add a variety of fruits, nuts, and grains, and sure. Lots of a variety of fiber, phytochemicals, vitamins, so on.

Do studies replicate the phytochemicals in vegetables? Vitamins, minerals and fiber are not the only healthy aspects of vegetables (also they tend to be low GI/GL, which is also good for you). Also low grade inflammation can contribute to chronic diseases, I don’t know if vegetables have ways to fight this aside from their vitamin and mineral content.

I don’t eat vegetables, but I do try to eat vegetable powders. I am currently taking this brand. Maybe not the exact same thing as taking broccoli in a pill, but as close as I can find.


But of course:
[li]The U.S. Preventive Services Task Force is pretty clear on the evidence against any cardiovascular/cancer benefit from vitamin supplements.[/li][li]The studies used in the Diet and Cancer Report show that certain types of vegetables “probably” reduce the risk of mouth, larynx, esophagus, and stomach cancer. And[/li][li]The Nurses’ Health Study showed that fruits and vegetables combined reduce the risk of cardiovascular disease by about 10% (i.e. a relative risk of roughly 0.9 for the 3 or 4 combinations studied).[/li][/ul]

There’s little question that there’s a benefit to vegetable (and fruit) consumption here. But, to my eyes, this benefit doesn’t seem all that huge. A 0.9 relative risk is a weak negative association. That doesn’t mean it’s worthless, but it does mean that it’s … weak. The Diet and Cancer Report studies look more promising on the surface, but most of them are case-control studies, and according to this article from the Harvard School of Public Health, case-control studies just aren’t very reliable – at least when compared with cohort studies. The few cohort studies there are in that list tend to show relative risks pretty close to 1, meaning “no correlation.”

That looks very interesting … except for the fact that the packaging seems to be loaded down with every food-woo buzzword ever invented. :dubious:

Does a .72 hazard ratio of dementia do anything to help convince you? And it does seem to be the vegetables more than the fruits that does it. (Cohort studies baby.) Even more broadly defined as cognitive decline, protective.

No question it is hard to say absolute proof in matters of diet. Long term randomized controlled studies are the gold standard and are not gonna happen. One always has to remain open to the possibility that some of the impact is what is not being eaten because the vegetables are being eaten instead as well. The statement however that diets high in vegetables, fruits, and whole grains, are associated with a wide variety of positive health outcomes is indisputable. And it is so far indisputable that no componant substitution (e.g. vitamin supplentation) accomplishes the same thing.

Ooh, that’s pretty big. Thanks for finding this.

I also note that (at least among people who didn’t carry the ApoE ε4 allele) omega-3 fatty acids and fish consumption correlated with a decreased risk of dementia, but excessive omega-6 fatty acid consumption correlated with an increased risk of dementia.

I’d better start eating more fish sticks!

Okay, I’ve incorporated those first 2 articles on dementia into Vegetable-Free Living, chapter 1.