Liver injury caused by herbals, dietary supplements rises in study
population
September 4, 2014
New research shows that liver injury caused by herbals and dietary supplements increased from 7% to 20% in a
U.S. study group over a ten-year period. According to the study published in Hepatology, a journal of the American
Association for the Study of Liver Diseases, liver injury caused by non-bodybuilding supplements is most severe,
occurring more often in middle-aged women and more frequently resulting in death or the need for transplantation
than liver injury from bodybuilding supplements or conventional medications."
Nearly half of all adult Americans consume herbal and dietary supplements with prior reports suggesting that is on
the rise. Medical evidence shows that supplements are used more often by women, non-Hispanic whites, those
over 40 years of age and those with more advanced education. Data from the National Health and Nutrition
Examination Survey (NHANES) III indicate that multivitamins, minerals, calcium and fish oils are the most
commonly used supplements.
"While many Americans believe supplements to be safe, government regulations (Dietary Supplement
Health and Education Act of 1994) require less safety evidence to market products than what is required
for conventional pharmaceuticals" explains lead author Dr. Victor Navarro, from Einstein Medical Center
Philadelphia. "With less stringent oversight for herbals and dietary supplements, there is greater potential for
harmful consequences including life-threatening conditions."
The present study examines hepatotoxicity due to supplements compared to medications, enrolling 839 patients
with liver injury from 8 U.S. DILIN referral centers between 2004 and 2013. Liver injury cases included 45 caused
by bodybuilding supplements, 85 attributed to non-bodybuilding supplements, and 709 due to medications. The
research team determined that among cases enrolled, liver injuries from herbal and dietary supplements rose to
20% during the study period. While bodybuilding supplements caused prolonged jaundice (median 91 days) in
young men, no fatalities or liver transplantations occurred. Death or liver transplantation occurred more frequently
among cases of injury from non-bodybuilding supplements, 13%, than from conventional medications, 3%. Liver
injury from non-bodybuilding supplements was more common in middle aged women.
© Cengage Learning 2015
What is a THEORY?
© Cengage Learning 2015
Biology
Concepts and Applications | 9e
Starr | Evers | Starr
Chapter 2
Life’s Chemical Basis
©
Learning2015
2015
© Cengage
Cengage Learning
What Are the Basic Building Blacks of All
Matter?
proton
neutron
electron
A
© Cengage Learning 2015
Rutherford’s Model of
the Atom
atomic radius ~ 100 pm = 1 x 10-10 m
nuclear radius ~ 5 x 10-3 pm = 5 x 10-15 m
If the atom is the new JETS Stadium
Then the nucleus is a marble on the 50 yard line
© Cengage Learning 2015
2.2
What Are the Basic Building Blacks of All
Matter?
• A typical atom has about the same number
of electrons and protons
• Atomic number: number of protons in the
atomic nucleus
• Element: pure substance that consists
only of atoms with the same number of
protons
• Periodic table: tabular arrangement of all
known elements by their atomic number
© Cengage Learning 2015
Isotopes and Radioisotopes
• Although all atoms of an element have the
same number of protons, they can differ in
the number of other subatomic particles
• Isotopes: forms of an element that differ in
the number of neutrons their atoms carry
• Mass number: total number of protons and
neutrons in the atomic nucleus
© Cengage Learning 2015
What Are the Basic Building Blacks of All
Matter?
B
atomic number
element symbol
mass number
elemental substance
element name
carbon
C
© Cengage Learning 2015
2.2 Why Do Atoms Interact?
• Electrons occupy different orbitals:
volumes of space around an atom’s
nucleus
• Orbitals are filled from lower to higher
energy
• The farther an electron is from the
nucleus, the greater its energy
© Cengage Learning 2015
Why Do Atoms Interact?
1
first shell
second shell
third shell
© Cengage Learning 2015
one proton
one electron
2
A The first shell
hydrogen (H)
helium (He)
6
8
10
carbon (C)
oxygen (O)
neon (Ne)
11
17
18
sodium (Na)
chlorine (Cl)
argon (Ar)
B The second shell
C The third shell
About Vacancies
• No vacancies: an atom’s outermost shell is
filled with electrons
– Most stable state
• Vacancy: an atom’s outermost shell has
room for another electron
– Chemically active; atoms interact with one
another
– Example: sodium atom has one electron in its
outer (third) shell, which can hold eight
© Cengage Learning 2015
About Vacancies
third shell
© Cengage Learning 2015
11
17
18
sodium (Na)
chlorine (Cl)
argon (Ar)
C The third shell
About Vacancies
electron loss
electron gain
Sodium atom
Sodium ion
11p+
11echarge: 0
11p+
10echarge: +1
A
© Cengage Learning 2015
Chlorine atom
17p+
17echarge: 0
B
Chlorine ion
17p+
18echarge: –1
How Do Ions Interact in Chemical Bonds?
one oxygen atom
two hydrogen atoms
© Cengage Learning 2015
Ionic Bonds
• Ionic bond: strong mutual attraction links
ions of opposite charge
– Ionically bonded sodium and chloride ions
make up sodium chloride (NaCl; table salt)
© Cengage Learning 2015
Ionic Bonds
Na+ Cl–
A
© Cengage Learning 2015
Ionic Bonds
ionic bond
B
© Cengage Learning 2015
Sodium ion
Chloride ion
11p+
10echarge: +1
17p+
17echarge: –1
Ionic Bonds
positive charge
C
© Cengage Learning 2015
negative charge
Covalent Bonds
• Covalent bond: two atoms share a pair of
electrons
– Formed between atoms with a small or no
difference in electronegativity
– Covalent bonds are often stronger than ionic
bonds (but not always)
© Cengage Learning 2015
Covalent Bonds
1
1
8
1
© Cengage Learning 2015
MOLECULAR HYDROGEN (H—H)
MOLECULAR OXYGEN (O=O)
8
8
1
WATER (H—O—H)
2.4 What Are The Life Sustaining
Properties of Water?
• Hydrogen bonding in water
– Water has unique properties that arise from
the two polar covalent bonds in each water
molecule
– In water, the oxygen atom carries a slight
negative charge; the hydrogen atoms carry a
slight positive charge
© Cengage Learning 2015
What Are The Life Sustaining Properties of
Water?
slight negative charge
A
© Cengage Learning 2015
slight positive charge
What Are The Life Sustaining Properties of
Water?
• Hydrogen bonding in water (cont’d.)
– The polarity of individual water molecules
attracts them to one another
– This type of interaction is called a hydrogen
bond
• Hydrogen bond: attraction between a covalently
bonded hydrogen atom and another atom taking
part in a separate polar covalent bond
© Cengage Learning 2015
What Are The Life Sustaining Properties of
Water?
a hydrogen bond
B
© Cengage Learning 2015
What Are The Life Sustaining Properties of
Water?
• Hydrogen bonding in water (cont’d.)
– Hydrogen bonds form and break much more
easily than covalent or ionic bonds
• Collectively they are quite strong
– Hydrogen bonds stabilize DNA and protein
structures
– Extensive hydrogen bonding among water
molecules gives liquid water several special
properties that make life possible
© Cengage Learning 2015
Water's Special Properties
• Water is an excellent solvent
– Substances that dissolve easily in water are
hydrophilic
– Ionic solids, such as sodium chloride (NaCl),
dissolve in water:
• The slight positive charge on each hydrogen atom
in a water molecule attracts negatively charged Cl–
• The slight negative charge on the oxygen atom
attracts positively charged Na+
© Cengage Learning 2015
Water's Special Properties
© Cengage Learning 2015
Water's Special Properties
• Water is an excellent solvent (cont’d.)
– Substances that resist dissolving in water are
hydrophobic (e.g., oils)
– Oils consist of nonpolar molecules, and
hydrogen bonds do not form between
nonpolar molecules and water
© Cengage Learning 2015
Water's Special Properties
• Water has cohesion
– Cohesion: tendency of molecules to resist
separating from one another
– Water has cohesion because hydrogen bonds
collectively exert a continuous pull on its
individual molecules
© Cengage Learning 2015
Evaporation from the leaves
Microscopic tubes
SEM
Cohesion due to
hydrogen bonds
between water
molecules
© Cengage Learning 2015
Figure 2.10
© Cengage Learning 2015
Figure 2.11
© Cengage Learning 2015
Water's Special Properties
• Water has cohesion (cont’d.)
– Cohesion takes energy
• Evaporation (transition of a liquid to a vapor) is
resisted by hydrogen bonding among water
molecules
© Cengage Learning 2015
Water's Special Properties
• Water stabilizes temperature
– Temperature: measure of molecular motion
– Because of hydrogen bonding, it takes more
heat to raise the temperature of water
compared with other liquids
– Below 0°C (32°F), water molecules become
locked in the bonding pattern of ice
• Sheets of ice that form on the surface of ponds,
lakes, and streams insulate the water
• Protects aquatic organisms during cold winters
© Cengage Learning 2015
© Cengage Learning 2015
Why is this so important???
© Cengage Learning 2015
Water's Special Properties
© Cengage Learning 2015
Why Are Hydrogen Ions Important in
Biological Systems?
• Concentration: amount of solute per unit
volume of solution
• pH: measure of the number of hydrogen
ions in a fluid
• Base: accepts hydrogen ions in water
– Above pH 7
• Acid: releases hydrogen ions in water
– Below pH 7
© Cengage Learning 2015
Why Are Hydrogen
Ions Important in
Biological
Systems? (cont’d.)
14 drain cleaner
13
oven cleaner
bleach
12 hair remover
11
household ammonia
milk of magnesia
10 hand soap
toothpaste
Tums
9 detergents
baking soda
8 seawater
egg white
blood, tears
7
pure water
6 milk
butter
corn
5 urine, tea, typical rain
black coffee
bread
4 beer
bananas
tomatoes, wine
3 orange juice
2
vinegar
cola
lemon juice
acid rain
1
gastric fluid
0
battery acid
Why Are Hydrogen Ions Important in
Biological Systems?
• The fluids inside cells stay within a
consistent range of pH because they are
buffered
• Most biological molecules can function
properly only within a narrow range of pH
– Buffer failure can be catastrophic in a
biological system
© Cengage Learning 2015
Why Are Hydrogen Ions Important in
Biological Systems?
• Burning fossil fuels such as coal releases
sulfur and nitrogen compounds that affect
the pH of rain
– Rainwater is not buffered
– In places with a lot of fossil fuel emissions, the
rain and fog can be more acidic than vinegar
© Cengage Learning 2015
Why Are Hydrogen Ions Important in
Biological Systems?
• The corrosive
effects of acid
rain is visible in
urban areas
© Cengage Learning 2015
Why Are Hydrogen Ions Important in
Biological Systems?
• Acid rain drastically changes the pH of
water in soil, lakes, and streams
• Such changes can overwhelm the
buffering capacity of fluids inside
organisms, with lethal effects
• Ocean pH????
© Cengage Learning 2015
2.6 Mercury Rising
• Mercury is a naturally occurring element
• Most of it is safely locked away in rocks
– Volcanic activity and human activity release it
into the atmosphere
© Cengage Learning 2015
Mercury Rising (cont’d.)
• Microbes combine airborne mercury with
carbon to form methylmercury
– Unlike mercury alone, methylmercury easily
crosses skin and mucous membranes
• When mercury enters the body, it
damages the nervous system, brain,
kidneys, and other organs
© Cengage Learning 2015
Mercury Rising (cont’d.)
• It takes months or years for mercury to be
cleared from the body
– The toxin can build up to high levels if even
small amounts are ingested on a regular basis
• Large predatory fish have a lot of mercury
– U.S. Environmental Protection Agency
recommends that adult humans ingest less
than 0.1 microgram of mercury per kilogram
of body weight per day
© Cengage Learning 2015
Mercury Rising (cont’d.)
© Cengage Learning 2015
– Twenty-five elements are essential to life.
– Four elements make up about 96% of the weight
of the human body:
• Oxygen
• Carbon
• Hydrogen
• Nitrogen
CHON
© Cengage Learning 2015
Carbon C: 18.5%
Oxygen O:
65.0%
Calcium Ca: 1.5%
Hydrogen H:
9.5%
Nitrogen N:
3.3%
© Cengage Learning 2015
Phosphorus P: 1.0%
Potassium K: 0.4%
Sulfur S: 0.3%
Sodium Na: 0.2%
Chlorine Cl: 0.2%
Magnesium Mg: 0.1%
Trace elements: less than 0.01%
Manganese Mn
Boron B
Chromium Cr Molybdenum Mo
Cobalt Co
Selenium Se
Silicon Si
Copper Cu
Tin Sn
Fluorine F
Vanadium V
Iodine I
Zinc Zn
Iron Fe
Figure 2.2
ORGANIC COMPOUNDS
– A cell is mostly water.
– The rest of the cell consists mainly of carbonbased molecules.
– Carbon forms large, complex, and diverse
molecules necessary for life’s functions.
– Organic compounds are carbon-based
molecules.
–C H O N
© Cengage Learning 2015
Organic Compounds?
•
•
•
•
•
•
•
CO2
H2O
C6H12O6
HCl
O3
C H O
CH4
12
22
© Cengage Learning 2015
11
Carbon Chemistry
– Carbon is a versatile atom.
• It has four electrons in an outer shell that holds eight.
• Carbon can share its electrons with other atoms to
form up to four covalent bonds.
– Carbon can use its bonds to
• Attach to other carbons
• Form an endless diversity of carbon skeletons
© Cengage Learning 2015
– The simplest organic compounds are
hydrocarbons, which are organic molecules
containing only carbon and hydrogen atoms.
– The simplest hydrocarbon is methane,
consisting of a single carbon atom bonded to
four hydrogen atoms.
© Cengage Learning 2015
– Larger hydrocarbons form fuels for engines.
– Hydrocarbons of fat molecules fuel our bodies.
© Cengage Learning 2015
Next Week:
Chapter 3
© Cengage Learning 2015
2.1 What Are the Basic Building Blacks of
All Matter?
• Positively charged protons (p+) and
uncharged neutrons are found in an
atom’s nucleus (core)
• Negatively charged electrons (e–) move
around the nucleus
– Charge: electrical property; opposite charges
attract, and like charges repel
© Cengage Learning 2015
Isotopes and Radioisotopes (cont’d.)
• Radioisotope: isotope with an unstable
nucleus
• Radioactive decay: process by which
atoms of a radioisotope emit energy
and/or subatomic particles when their
nucleus spontaneously breaks up
© Cengage Learning 2015
Isotopes and Radioisotopes (cont’d.)
nucleus of 14C, with
6 protons, 8 neutrons
© Cengage Learning 2015
nucleus of 14N, with
7 protons, 7 neutrons
Tracers
• All isotopes of an element generally have
the same chemical properties regardless
of the number of neutrons in their atoms
• Radioisotopes can be used as tracers to
study biological processes
– Tracer: any substance with a detectable
component
© Cengage Learning 2015
Why Do Atoms Interact? (cont’d.)
• An electron can move to a higher energy
orbital if an input gives it a boost
– Electron then immediately emits the extra
energy and moves back down to the lower
energy orbital
© Cengage Learning 2015
Why Do Atoms Interact? (cont’d.)
• A shell model helps us visualize how
electrons populate atoms
• Nested “shells” correspond to successively
higher energy levels
• Each shell includes all of the orbitals on
one energy level
© Cengage Learning 2015
About Vacancies (cont’d.)
• Solitary atoms that have unpaired
electrons are called free radicals
– Typically very unstable
• Atoms with an unequal number of protons
and electrons are called ions
– Carry a net (overall) charge
© Cengage Learning 2015
2.3 How Do Ions Interact in Chemical
Bonds?
• An atom can get rid of vacancies by
participating in a chemical bond with
another atom
– Chemical bond: attractive force that arises
between two atoms when their electrons
interact
– Compound: molecule that has atoms of more
than one element
© Cengage Learning 2015
Ionic Bonds (cont’d.)
• Ions retain their respective charges when
participating in an ionic bond
– Polarity: separation of charge into positive
and negative regions
– A NaCl molecule is polar because the chloride
ion keeps a very strong hold on its extra
electron
– Electronegativity: measure of the ability of an
atom to pull electrons away from other atoms
© Cengage Learning 2015
Covalent Bonds (cont’d.)
• Structural formulas: lines between atoms
represent the number of covalent bonds
– Example: H-H
• H2 has one covalent bond between the atoms
– Example: O=O
• A double bond links the two oxygen atoms
– Example: N=N
• A triple covalent bond links the two nitrogen atoms
© Cengage Learning 2015
Covalent Bonds (cont’d.)
© Cengage Learning 2015
Covalent Bonds (cont’d.)
• Covalent bonds in compounds are usually
polar
• Atoms share electrons unequally in a polar
covalent bond
– Example: water molecules
© Cengage Learning 2015
Water's Special Properties (cont’d.)
• Hydrogen bonds among many water
molecules are collectively stronger than an
ionic bond between two ions
– The solid dissolves as water molecules tug
the ions apart and surround each one
© Cengage Learning 2015
Water's Special Properties (cont’d.)
• Water is an excellent solvent (cont’d.)
– Salt: releases ions other than H+ and OH–
when it dissolves in water (e.g., NaCl)
– Solute: a dissolved substance
– Solution: uniform mixture of solute completely
dissolved in solvent
• Chemical bonds do not form between molecules of
solute and solvent
– Nonionic solids (e.g., sugars) dissolve easily
in water due to hydrogen bonding with water
© Cengage Learning 2015
2.5 Why Are Hydrogen Ions Important in
Biological Systems?
• When water is liquid, some of its
molecules spontaneously separate into
hydrogen ions (H+) and hydroxide ions
(OH–)
• These ions can combine again to form
water:
© Cengage Learning 2015
Why Are Hydrogen Ions Important in
Biological Systems? (cont’d.)
• Buffer: set of chemicals that can keep the
pH of a solution stable by alternately
donating and accepting ions that
contribute to pH
© Cengage Learning 2015