Latest Headlines
0

Plant-Based Foods – A Tricky PubMed Search – Revised 2016

HardinLib0902

By Eric Rumsey, Janna Lawrence and Xiaomei Gu

As we discussed in an article earlier this year, searching for nutrition in PubMed has improved greatly since NLM brought the subject together in one explosion (Diet, Food, and Nutrition). This ability to search the field of nutrition easily has helped in searching for plant-based foods [PBFs] in some ways. But in other ways, it’s still as difficult as it was when we wrote our 2013 article on the same topic.

The basic problem in searching for PBFs, just as it was before the addition of the new explosion, is that a large proportion of PBFs are not in the Food explosion, but are only in Plants, and not in Food. So the fact that Food is part of the new inclusive explosion doesn’t make it any easier to search for PBFs.

In addition to the fact that most fruits and vegetables are treated as plants instead of foods, another problem in searching for them is that almost all of them are put under their botanical, Latin names, that are not recognizable to most people. Here are some examples, all of which are in the plant-taxonomic branch of the MeSH tree:

  • Kale is Brassica
  • Sweet potato is Ipomoea batatas
  • Plum is Prunus domestica
  • Almond is Prunus dulcis
  • Apple is Malus
  • Cranberry is Vaccinium macrocarpon
  • Strawberry is Fragaria
  • Kidney Beans is Phaseolus
  • Chocolate is Cacao
  • Turmeric is Curcuma

If you’re searching for specific food plants, the Latin MeSH terms are usually not a problem, because when you search for a common name, it’s mapped to the botanical MeSH term (e.g. if you search for Grapes, it maps to Vitis). The problem comes if you want to browse the Plants explosion to pick out the edible plants from the many plants that are not edible, because only the botanical names are listed. The Rose family (Rosaceae) of plants, for example, has several edible species within it. There are 19 genera listed in MeSH in the family, and 6 of them have edible species. But to find them, you have to be able to pick out the genera with edible species (e.g. Malus, Prunus) from the others (e.g. Agrimonia, Alchemilla).

If you’re interested in learning about how to search for PBFs in PubMed, see our companion article, which includes an updated “search recipe,” or hedge.

[Image above is public domain, from WikiMedia]

0

US Lags Behind The World In Plant-Based Food Research

By Xiaomei Gu, Eric Rumsey and Janna Lawrence

In our explorations of plant-base foods (PBFs) in PubMed, it’s often striking that there are many excellent articles from non-US countries. So we did a survey in PubMed to measure different countries’ authorship of articles on PBFs, and we found that, indeed, several countries have a much higher proportion of their total articles on PBFs than the US.

The charts below show our data for all PBFs and for four specific foods or food groups. The charts are based on the percentage of articles from each county, not the total number of articles. So even though the total number of articles on PBFs by US authors may be higher than other countries, the proportion of articles on PBFs is substantially lower. [The charts are from a poster presented at MLA in 2016. For more details on our survey methods, see the poster.]

hardinlibPosterPBFcountriesLeadPubMed search strategy used to find plant-based foods in chart above is described here.

…………….

hardinlibPosterPBFcountriesCabbage

hardinlibPosterPBFcountriesNuts

hardinlibPosterPBFcountriesFruit

hardinlibPosterPBFcountriesSpices

0

Nuts as a Healthy Food: How to Search in PubMed

By Eric Rumsey, Janna Lawrence and Xiaomei Gu

This article is based on a poster presented at the Medical Library Association annual meeting, Toronto, May 2016.

Introduction

Searching for nuts as food is difficult. As with most plant-based foods, MeSH terms for specific types of nuts are in the Plants explosion instead of in the food explosion. Nuts are especially tricky because the MeSH term Nuts is not an explosion, and most articles on specific types of nuts are not indexed to the term Nuts. So it’s necessary to search for specific nuts to retrieve articles on them.

A caveat—As with nutrition topics in general, and plant-based foods in particular, searching in PubMed is complicated, largely because many plant-based substances are used as foods and also as medicines or experimental organisms. A list of articles on specific nut types is likely to contain some articles that are not food-related.

Searching for Nut Types

The general idea of searching for specific types of nuts is simple: Do an OR search that includes the common name and botanical name. In most cases, articles on a specific nut type will be indexed under the botanical name, but using the common name is always a good idea. See the example below for searching walnuts.

walnut [tiab] OR walnuts [tiab] OR juglans [MeSH]

It is necessary to restrict the search for the common names to the title and abstract [tiab] fields because there are many streets in the Address field that are named after nuts (e.g., 975 Walnut St.).

hardinlibPosterNutsAlmonds

Image 1. Almonds

 

hardinlibPosterNutsWalnuts

Image 2. Walnuts

 

hardinlibPosterNutsHazelnuts

Image 3. Hazelnuts

 

hardinlibPosterNutsCashews

Image 4. Cashews

 

hardinlibPosterNutsPecans

Image 5. Pecans

 

hardinlibPosterNutsBrazils

Image 6. Brazil Nuts

 

Peanuts Are Different!

hardinlibPosterNutsPeanuts

Image 7. Peanuts

Peanuts are a special case. Unlike the other nuts here, they grow on herbaceous plants instead of on trees and, as members of the bean family, they are nutritionally more closely related to beans than to other nuts. There is also a separate MeSH term, Peanut Hypersensitivity, dealing with peanut allergies.

Because peanuts are commonly used as experimental plants, many of the articles about them are not related to nutrition. To  focus on nutritional aspects, we suggest incorporating the Diet, Food, and Nutrition explosion into the search:

(peanut [tiab] OR peanuts [tiab] OR arachis [mh])

AND Diet, Food, and Nutrition [mh]

Citations: 2932

0

Great but Hidden: PubMed’s New Diet, Food, and Nutrition Explosion

By Eric Rumsey, Janna Lawrence and Xiaomei Gu

As we have written, NLM made a great improvement in introducing the new explosion for Diet, Food, and Nutrition. Before that was introduced this year, each of the three elements in the explosion had to be searched separately because they were not in the same explosion. So we strongly endorse the new explosion!

Although it is less difficult to search for nutrition articles now, there is still a problem. The term mapping feature of PubMed does not work for the word “nutrition,” which is certainly a common way to search for the broad subject comprised by the new explosion.

Hardin0511b2-300x247

Image 1. Search Details for Heart Attack.

In most cases in PubMed, if the user searches a word or term that’s synonymous with the appropriate MeSH term, the system will automatically include the MeSH term in the search. An example of this is searching for the term heart attack (without quotes).

As shown in Image 1, PubMed automatically maps the word to the appropriate MeSH term – “myocardial infarction” [MeSH Terms]. (To see Search details, on the PubMed search results screen, scroll down to the “Search details” box, in the right side-bar). Another example of PubMed’s automatic mapping is cancer, which maps to neoplasms [MeSH Terms].

Hardin0511c2-300x279

Image 2. Search Details for Nutrition.

A search for the word nutrition retrieves several phrases and MeSH terms, seen in the Search details in Image 2. But this does not include the new explosion Diet, Food, and Nutrition, which would retrieve many more relevant articles than these terms do.

There are two conceivable ways that NLM could address this problem. The first is to change the name of the explosion to Nutrition, so that mapping the word would not be necessary. The second solution is to make the word nutrition map to the new explosion. We encourage NLM to consider these options, so that the full power of the new explosion can be released!

0

Plant-Based Foods – An Inclusive PubMed Search – Revised 2016

Hardin0318c

By Eric Rumsey, Janna Lawrence and Xiaomei Gu

Searching for nutrition topics in PubMed is tricky. It’s especially difficult to search for plant-based foods (PBF’s). In 2014, we published an article that addresses this problem that contained a hedge for searching for PBF’s. A few months ago, the National Library of Medicine introduced a new explosion that makes it a lot easier to search for nutrition topics in PubMed, which we discussed here.

In this article we are revising our 2014 PBF hedge to incorporate the new PubMed explosion. While there may still be a few occasions when our previous hedge for PBF’s would be appropriate, in almost all cases we do not recommend using the old hedge. Instead, we recommend using the hedge below:

((Plants[mesh] OR Plant Preparations[mesh]) AND Diet, Food, and Nutrition [mesh]) OR (Vegetables[mesh] OR Fruit[mesh] OR Plants, Edible [mesh] OR Dietary Fiber[mesh] OR Flour[mesh] OR Bread[mesh] OR Diet, Vegetarian[mesh] OR Nuts[mesh] OR Condiments[mesh] OR Vegetable Proteins[mesh] OR Tea[mesh] OR Coffee[mesh] OR Wine[mesh] OR Vegetable Products[mesh])

The big change in this PBF hedge from the previous PBF hedge is, of course, replacing the food-diet-nutrition hedge that was part of the previous PBF hedge with the the new Diet, Food, and Nutrition explosion. Otherwise, the main change is the addition of the new MeSH term Vegetable Products.

Advanced techniques for plant-based food searching

In most cases, you’ll probably want to start with the hedge above. But if that doesn’t find what you want, try the ideas below.

If you combine your subject (a particular disease for example) with the hedge above and it misses articles that you think exist, consider broadening the search by combining your subject with Plants. The Plants explosion in MeSH is very large, containing hundreds of plant species. It’s organized by taxonomic relationships, which makes it hard for a non-botanist to browse. But it’s useful to combine with other subjects in searching, because it’s so comprehensive. The main drawback in searching it is that in addition to plant-based foods, it also has many plant-based drugs, which you’ll have to sift out from the food articles.

If you combine your subject with the hedge above and it misses articles on particular plant-based foods, search specifically for those. If you do a search for food and migraine, for example, and your search doesn’t pick up specific foods that you know have been associated with migraine (e.g. chocolate), combine those foods specifically with migraine.

A caveat: There is an exploded MeSH term Plants, Edible, which might seem to be a good place to search for plant-based foods. Unfortunately, however, it’s of limited usefulness – The explosion contains only grain plants and Vegetables, which is mainly soy-based foods. The term Plants, Edible itself is mostly used to index articles that are on the general concept rather than articles on specific types of edible plants.

If you’re interested in reading some background explaining why it’s so difficult to search for PBFs in PubMed, see our companion article.

0

Diet, Food, and Nutrition – How To Search in PubMed

hardin0318a

By Eric Rumsey, Janna Lawrence and Xiaomei Gu

Searching for Food, Diet & Nutrition has long been one of the most difficult subjects to search in PubMed. We were happy to report earlier this year that the National Library of Medicine has gone a long way toward fixing this problem, with a new explosion for Diet, Food, and Nutrition.

Before the new explosion came out, searching for the subject was very tricky because diet, food and nutrition were all in different places in the MeSH tree structure, and so they had to be searched separately. To help with this problem, we created a detailed search strategy, or hedge, that would bring together all of the components in one search. We no longer recommend using this hedge. We have examined the new explosion, and find that it covers the field very adequately.

We strongly recommend the new explosion for most nutrition searches. But there are some aspects of the field that are not covered in the new explosion that were part of our hedge, in particular obesity and vitamins. Both of these terms are closely connected to the subject of food, diet & nutrition. But we understand why NLM has not included them in the new explosion, since they will not always be wanted. Both of these subjects are somewhat complicated to search in PubMed. In both cases, however, a simple one-word text word search will retrieve almost all of the relevant citations. So in cases when you want to include these subjects in your nutrition searching, you can do these searches:

Diet, Food, and Nutrition [mh] OR vitamins
Diet, Food, and Nutrition [mh] OR obesity
Diet, Food, and Nutrition [mh] OR vitamins OR obesity

“Good job, NLM!”

In conclusion, good words for the National Library of Medicine – Thank you for fixing the long-standing problem in searching for nutrition! With the surging interest in the subject, you’ve made things a lot easier for the many people searching for it.