Fat,CHO, water and micronutrients for adults Flashcards Preview

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Flashcards in Fat,CHO, water and micronutrients for adults Deck (136)
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Why omega 6 to omega 3 is very important

Eicosanoid products derived from omega-6 PUFAs (such as prostaglandin (PG) E2 and leukotriene (LT) B4 synthesized from arachidonic acid (AA)) are more potent mediators of thrombosis and inflammation than similar products derived from omega-3 PUFAs 

omega 3 and omega 6 compete for the same enzyme desaturase


Requirements for omega 6 and omega 3 are set based on

-AI for C18:2n-6 and C18:3n-3 established based on highest median intakes in US populations where no evidence of deficiency


Why fatty acids requirements go down with age (in elderly)

As body weight goes down, then the requirement goes down

And their intake is lower ( caloric intake)


What is the rate fo glucose production in overnight fasted adults

2.8-3.6 g/kg/day from glycogen and gluconeogenesis

•~ 210 to 270 g/d in a 70 kg man (without using ketoacids)

•~50% from glycogenolysis & 50% from gluconeogenesis


Min CHO determined by


•by the brain’s requirement

•Uses glucose almost exclusively for its energy needs

•~110-140 g/d in adults


What happens in subject with CHO metabolism in starvation

•In subjects fully adapted to starvation

•Ketoacid oxidation: ~ 80% of brain’s energy requirements

à only 22 to 28 g/d of glucose required


CHO EAR is based on and what assumptions it makes

•EAR based on amount that would provide the brain with adequate supply of glucose

•Without additional glucose production from protein or TG

•Without ↑ketones greater than observed after o/n fast


•This assumes:

1.Energy sufficient diet with AMDR of CHO (45 – 65%)

2.à glucose not limiting to the brain (no use of ketoacids)


Is there difference in oxidation between age and sex in CHO?

There is no proof


Amount of dietary CHO to decrease risk of chronic disease



Definitions of fiber

•Nondigestible CHOs & lignin intrinsic & intact in plants


What is functional fiber and what is total fiber

•Functional fiber = isolated, nondigestible CHOs shown to have beneficial physiological effects in humans

•Total fiber = Dietary Fiber + Functional Fiber


What is resistant starch

Resistant starch- CHO rich source ( like pasta) part of the pasta is not broken down in upper digestion and it is the source of fermentation for bacteria in the colon


How can you cook potatoes ,so there will be more resistant starch

Cooked and then cooled


Benefits of fiber

Fiber- satiety, protection from obesity and weight gain (especially from cereal), in part because of satiety and in addition because they have a probiotic effect -> the greater the diversity, greater the protection

Cereal fiber increases bacterial diversity which is associated with a variety of health benefits and conversely a low bacterial diversity leading to unwanted weight gain or increased disease risk

1.Ameliorate constipation & diverticular disease

2.Fuel for colonic cells

3.↓ blood [glucose] and [lipids]

4.Source of nutrient-rich low-energy foods à satiety & ↓risk of obesity


What is the best food to romote bacterial diversity

Wheat bran

A simple dietary modification to consume a daily bowl of a high fiber breakfast appears to have a positive impact on the gut microbiota for health adults   which can be measured within the first 3 weeks

As little as 6 g of wheat fiber was shown to produce significant positive benefits to the gut microbiota, 


How fiber can help with diverticulosis

Provide bulk and decrease the transition time


How fiber can be fuel for colonic cells if fiber is not digested

SCFAs from fermentation can be used as a fuel (butyrate) and it has been linked with decreased risk of colonic cancer


Why fiber requirements go down with age?

Due to decrease in caloric requirements


what kind of fiber has the greatest effect on CHD risk

Cereal fiber & proven Functional Fibers, including psyllium & pectin

-Certain kinds of fiber bind cholesterol & prevent absorption -> ↓CHD risk


Why there is a recommendation for fiber, but no EAR

-Strong data on relationship between dietary fiber intake and CHD risk -> use to set intake recommendation.

-Benefit of ↑Total Fiber intake: continuous across range of intakes à EAR cannot be made.


What nutrient is the largest constituent of the human body



Water is essential for and what are the components for total water intake

•Essential for cellular homeostasis and life

•Total water intake = drinking water + water in beverages (80%)  + water that is part of food (20%)


What happens if you take too much water and what happns to elderly with too little intake and what adivce can be given to avoid it

  • Elderly population is less sensitive to thirst and thus can become dehydrated and pose risk to heart attack and platelet aggregation to blood clots
  • A glass of water before bedtime can decrease the chance of stroke


  • If too much: risk of edema and oxygen cannot rich the tissues
  • With dehydration you have more risk of falling due to low pressure


Do we drink by thrist or something else and do we drink enough 

Most healthy adults consume enough water and behavior daily fluid intake , not thirst


When you have thirst signals


•↓Body water (sensed as a low blood volume)

•↑ [Na] (primarily sensed by cells of the brain)


What hormone plays a role in water levels in the body? what are the risks for chronic dehydration? How water, ADH and insulin resistance are connected

ADH plays a role in keeping water inside the body

One risks for chronic dehydration is decreased metabolic response to dehydration ( when high CHO intake->chronic water dehydration-> not enough vasopressin secreted -> insulin resistance

ADH acts on insulin receptors blunting the action


How water status is assessed

•Hydration status (assessed by plasma or serum osmolality) = primary indicator of water status

•Physical activity, environmental and dietary conditions: substantial influences on water needs


How dietary factors can influence water requirements

•Dietary factors also influence water requirements

•Osmotic load created by

•Metabolizing dietary protein & organic compounds

•Varying intakes of electrolytes


Is there a definite daily water requirenment for a given person?

No, single requirement


Dehydration will lead to

->Impaired heat dissipation

->↑Body core temperature

->↑ strain on CV system