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@node Top
@titlepage
@title GNUtrition
@subtitle Version 0.33rc1
@subtitle $Id: gnutrition.texi,v 1.1 2026/05/08 23:18:25 asm Exp $
@author @uref{https://antonm.org/, Anton McClure} @email{asm@@gnu.org, <asm@@gnu.org>}
@author Edgar Denny
@author Ian Haywood
@end titlepage

@ifhtml
Version 0.33rc1
@*
$Id: gnutrition.texi,v 1.1 2026/05/08 23:18:25 asm Exp $

@uref{https://antonm.org/, Anton McClure} @email{asm@@gnu.org, <asm@@gnu.org>}
@*
Edgar Denny
@*
Ian Haywood
@html
<hr>
@end html
@end ifhtml

@menu
* Introduction::
* The Main Window::
* The Main GUI Window::
* The Nutrients in GNUtrition::
* GNU Free Documentation License::
* Bibliography::
@end menu

@node Introduction
@chapter Introduction
@anchor{#introduction}
GNUtrition is a program designed to produce a detailed nutritional
analysis of the human diet.

@menu
* Downloading GNUtrition::
* Running GNUtrition for the First Time::
@end menu

@node Downloading GNUtrition
@section Downloading GNUtrition
@anchor{#downloading-gnutrition}
GNUtrition is is freely available at
@uref{http://www.gnu.org/software/gnutrition,www.gnu.org}. It is
released under the GNU General Public Licence version 3 or later. See
the file @code{LICENCE} for details.

@menu
* Requirements::
@end menu

@node Requirements
@subsection Requirements
@anchor{#requirements}
GNUtrition requires the following packages:

Build-time

@itemize
@item
GNU Make

@item
C compiler with C99 support (e.g., GCC)

@item
ncurses development headers and library

@item
sqlite3 development headers and library

@item
libm (typically part of the C standard library on GNU/Linux)

@end itemize

Run-time

@itemize
@item
ncurses library

@item
sqlite3 library

@item
A USDA food database (@code{food.db}) built with @code{build_db.sh}

@end itemize

This list looks daunting, but all of these packages should be standard
on modern Linux systems, but you may have to install SQLite separately.

@node Running GNUtrition for the First Time
@section Running GNUtrition for the First Time
@anchor{#running-gnutrition-for-the-first-time}
Install the database used for food information first:

@verbatim
$./build_db.sh
@end verbatim

Then you can start GNUtrition for the command-line simply:

@verbatim
$gnutrition
@end verbatim

@menu
* Entering your Information::
@end menu

@node Entering your Information
@subsection Entering your Information
@anchor{#entering-your-information}
The profile options give you the option to enter your age in years, your
current height, your current weight, and your activity level. This is
subject to change prior to GNUtrition 1.0.

@node The Main Window
@chapter The Main Window
@anchor{#the-main-window}
The main window shows you a daily budget based on USDA recommendations,
along with the following options

@itemize
@item
s @code{Search}

@item
l @code{Log}

@item
p @code{Profile}

@item
q @code{Quit}

@end itemize

The search tool lets you search by food names and descriptions.

The log lets you view foods you add, and lets you edit those entries.

@node The Main GUI Window
@chapter The Main GUI Window
@anchor{#the-main-gui-window}
At the top of the new main window is Search, Profile, and About.

Under that, you have both a daily budget based on USDA recommendations,
along a daily food log.

The search window lets you search by food names and descriptions.

@node The Nutrients in GNUtrition
@chapter The Nutrients in GNUtrition
@anchor{#notes}
This chapter contains some notes on the nutrients analysed by
GNUtrition. They are not a definitive guide, for detailed information
refer to a standard text of nutrition or dietetics.

@menu
* Caveat::
* Macro nutrients::
* Vitamins::
* Metals::
* Amino acids::
* Lipids::
@end menu

@node Caveat
@section Caveat
@anchor{#caveat}
When Ian was researching the information for the Recommended Daily
Intakes (RDIs). he found the information conflicting but incomplete, so
for some nutrients there may be a European value, a US value, and a UN
value. In general, he chose the US value, in the hope this will be
compatible with the database.

If you know of a good reference for RDIs, we would be eager to hear from
you, mail us at
@uref{mailto:bug-gnutrition@@gnu.org,bug-gnutrition@@gnu.org}

It also should be noted that RDIs are a @emph{guide} to nutrition, not
the definition of it. Individuals may vary from the RDIs provided for
many reasons. For example, active people need more energy and protein
than inactive people, and illness increases the RDIs for almost
everything.

In summary, just because the program spits out a nice column of
``100%'', that doesn't automatically mean you have a healthy diet. The
old rules about balance and lots of green vegetables still apply, we're
afraid.

@node Macro nutrients
@section Macro nutrients
@anchor{#macro-nutrients}
Macro nutrients constitute the bulk of the food we eat, they provide
energy and chemical building-blocks for tissues.

@table @asis
@item Protein

Proteins consists of long chains of @ref{#acids,amino acids} , to which
it is broken down to in the digestive system. Much of these amino acids
are reconstituted by the body to form human proteins. Human proteins are
universal in the body: as enzymes they regulate chemical reactions
within cells and the blood, they form tendons and ligaments which hold
the body together, and they provide muscle with its ability to contract.
Excess protein can be converted to sugar by the liver.

@item Carbohydrate

consists of sugar, and chains of sugar molecules called starches.
Starches are broken down in a similar manner to protein. In plants and
bacteria, carbohydrates provide structure, but in animals they are used
for energy.

@item Fat

consists of fatty acids (@ref{#lipids,lipids}), which are chain of
carbon atoms with a acid group at the end. These fatty acids are linked
in groups of three by glycerol. Once again,. this structure is broken
down in the gut, only to be re-formed in fat cells. Some fatty acids
have special functions, but mostly fat is a store of energy.

@item Alcohol

Rightfully a drug, but its energy component, between fat and protein,
can be significant in some people. There is no recommended intake for
alcohol, but their are recommended maximum intakes, these being 40g a
day for men and 20g a day for women. @footnote{according to the Drug and
Alcohol Centre, St. Vincent's Hospital, Melbourne, Australia.}

@item Energy

A total calculated from the above, which is expressed in both
kilocalories (the traditional unit in chemistry), and kilojoules (the
physicist's unit).

There is a base requirement for energy, which can be estimated by age
and weight. However, muscle mass requires more energy to maintain than
fat mass, so persons of the same weight can have widely different base
energy requirements. In addition, active people will obviously need more
energy.

@item Fibre

is indigestible by human enzymes, and is largely excreted, or digested
by bacteria in the large intestine. Nevertheless, it is very important,
and often deficient in first-world diets. It dilutes toxins that build
up the gut and retains water. It softens faeces and increases its
volume, making bowel motions more efficient. Deficiency causes
constipation, and has been linked to bowel cancer.

@item Water

Arguably the most important nutrient, in terms of amount (two-thirds of
the body), and essentiality (people die of thirst long before they
starve).

@end table

@node Vitamins
@section Vitamins
@anchor{#vitamins}
Vitamins are cofactors -- special molecules which support various
biochemical reactions with in the body -- required only in very small
amounts, and can be stored for extended periods. They are divided into
two groups:

@menu
* Fat-soluble vitamins::
* Water-soluble vitamins::
@end menu

@node Fat-soluble vitamins
@subsection Fat-soluble vitamins
@anchor{#fat-soluble-vitamins}
@table @asis
@item Vitamin A

is used for light-detecting chemicals in the retina of the eye, and
maintaining proper skin moisture and softness. In deficiency, poor night
vision, hard and rough skin, and anaemia can occur. Vitamin A is also an
anti-oxidant and protects against cancer.

@item Vitamin D

regulates calcium. Deficiency leads to rickets (soft, malformed bones)
in children. With adequate sunlight, the body can make its own vitamin
D, so little or none is required by the diet. It is not included in the
USDA database, and so not analysed by GNUtrition.

@item Vitamin E

is a strong anti-oxidant: it destroys cancer-causing chemicals called
@@emph@{free radicals@}. No deficiency syndrome has been described.

@item Vitamin K

is used by the liver to make special proteins, which circulate in the
blood. When a person is injured, these proteins. help to form a clot.
Intestinal bacteria can make vitamin K, however, it is also required in
the diet, but in low amounts. It is not included in the database.

@end table

@node Water-soluble vitamins
@subsection Water-soluble vitamins
@anchor{#water-soluble-vitamins}
@table @asis
@item Vitamin C

is used in making collagen, a tough protein that provides a ``glue''
holding cells together. Vitamin C deficiency, known as @@emph@{scurvy@},
leads to easy bruising and bleeding, as lack of collagen weakens blood
vessels. It also aids the absorption of of iron, and may be an
anti-oxidant.

It is not a cure for the common cold.

@item Vitamin B-1 (Thiamine)

is used in the biochemical processes by which cells obtain energy from
sugar. Deficiency causes mental disturbance, clumsiness, and
double-vision, which can occur in alcoholics, and in third-world
countries.

@item Riboflavin; Niacin; Pantothenic acid

are also important in energy utilisation by cells, by forming parts of
different enzymes. Niacin deficiency causes @@emph@{pellagra@},
characterised to dermatitis, diarrhoea, and dementia.

@item Vitamin B-6 (pyridoxine)

is used for processing of amino acids, deficiency causes a type of
anaemia.

@item Folate

is used for the synthesis of DNA. Deficiency leads to anaemia. In
pregnant women, higher intakes protects against neural tube defects in
their children.

@item Vitamin B-12

is also used for DNA synthesis, also leads to anaemia when deficient.
Only available in animal sources, so strict vegans require
supplementation.

@end table

@node Metals
@section Metals
@anchor{#metals}
@table @asis
@item Iron

is used mainly in haemoglobin, a chemical that binds oxygen in the
blood, giving it its red colour. Deficiency, more common in women, leads
to mild anaemia.

@item Calcium

is used mainly in bones, to provide mechanical strength. Low calcium
intake has been linked to osteoporosis (weakening of the bones) in old
people.

@item Selenium

is essential to an anti-oxidant enzyme, which works in a similar manner
to Vitamin E.

@item Potassium; Sodium

are used to provide electrical potentials across nerve and muscle cell
membranes, also to provide the necessary osmotic force in body fluids.
Excess sodium was once linked to high blood pressure, but this not
emphasised today.

@item Magnesium

is used in controlling nerve impulses, deficiency causes weakness and
tremors.

@item Copper; Manganese; Zinc

combine with specific proteins to form various different enzymes.

@end table

@node Amino acids
@section Amino acids
@anchor{#acids}
Amino acids are the breakdown products of proteins. They are divided
into two groups, essential and non-essential:

@float Table
@multitable {Phenylalanine} {Non-essential} 
@headitem 
Essential
 @tab Non-essential
@item 
Histidine
 @tab Glycine
@item 
Isoleucine
 @tab Glutamate
@item 
Leucine
 @tab Aspartate
@item 
Lysine
 @tab Proline
@item 
Methionine
 @tab Serine
@item 
Phenylalanine
 @tab Alanine
@item 
Threonine
 @tab Tryptophan
@item 
Tryptophan
 @tab Arginine
@item 
Valine
 @tab 
@end multitable
@caption{The Amino Acids}
@end float
Deficiency of any of the nine leads to wasting as proteins cannot be
made without them. This usually only occurs with a very monotonous vegan
diet, where the chief food is a plant that does not have one or more
essential amino acid. A varied vegetarian diet solves the problem.

The other amino acids can be synthesised by the liver. The liver can
also interchange two pairs: cysteine and methionine, and tyrosine and
phenylalanine. This means a shortage of one can be made up from the
other, so total as the total requirement is met.

Amino acid supplements are of no proven benefit over proteins containing
the amino acids (but are much more expensive).

@node Lipids
@section Lipids
@anchor{#lipids}
Lipids include fatty acids (breakdown products of fat) and cholesterol.

@table @asis
@item Fatty acids

can be divided into three main groups: saturated @footnote{`saturation'
in this sense refers to hydrogen. Ask an organic chemist.},
mono-unsaturated and polyunsaturated. With these three the key is the
@emph{ratio} -- lots of saturated fatty acids, relative to the others
leads to atherosclerosis (hardening of the arteries).

Their specific chemical structures are available in organic chemistry or
biochemistry textbooks, in general they consists of a vary chain of
carbon-atoms, with a carboxylic acid group at one end.

Fatty acids are used to make certain types of hormones, as well as to
store energy. Two fatty acids, linoleic and alpha-linoleic acid, are
essential for humans.

@item Omega-3, and -6

Some fatty acids are referred as "omega-3" and "omega-6". This refers to
the location of a double bond from the final (omega) carbon atom in the
fatty acid.

It is believed that omega-3 fatty acids, found in fish oil, may have
beneficial health effects, but there is little hard evidence for this.

@item Cholesterol

can be made by the liver, so there is little dietary need. When we eat
cholesterol, the liver compensates by making less. Contrary to popular
belief, dietary cholesterol seems to have little effect on
blood-cholesterol levels, instead saturated fatty acids seem to be more
important.

@item Phytosterols

Not sure about these. Many be one and the same as phyto-oestrogens,
plant mimics of the female sex hormone. Intake is believed to control
symptoms of menopause.

@end table

@node GNU Free Documentation License
@chapter GNU Free Documentation License
@anchor{#gfdl}
@include gfdl.texi

@node Bibliography
@chapter Bibliography
@anchor{#bibliography}

Robert Bateman, Hamlyn, @emph{Every Boy's Handbook}, 1960.
David Bender and Arnold Bender, Oxford, @emph{Nutrition: A reference
handbook}, 1997.

Stephen G. Chancy, Wiley-Liss, @emph{Principles of Nutrition I & II},
1997.

@emph{Textbook of Biochemistry}, Edited by Thomas Devlin.
Lubert Stryer, W. H. Freeman, @emph{Biochemistry, 4th ed.}, 1995.

U.S. Department of Agriculture, Agricultural Research Service,
@emph{@uref{http://www.ars.usda.gov/ba/bhnrc/ndl,@emph{Nutrient Database
of Standard Reference, Relase 21}}} , 2008.

@bye