New Under the Sun:
Volume 1, Issue 7
Greetings!! July marks the transition between the first and second halves of the year. This is a good point to think about where we have been and where we are planning to go. To help keep your health optimal, a handy checklist of appropriate actions has been included in this month’s Tip section.
News Updates: This month’s topics are a diverse selection: the effects of emotions on the brain; egg yolks for infant health; and the impact of diet on age at menarche.
Emotions and the Brain: A variety of research studies have shown that all individuals respond to threatening faces in the same manner: the amygdala, the tiny portion of the brain associated with emotion, is strongly activated. When neutral faces are shown, the amygdala remains inactive. Recently, another set of researchers decided to see how different personality types respond to happy faces. What they found was that those who fell into the extroverted category tended to have an active amygdala when shown happy faces, but that the amygdala remained inactive for those described as introverted. The researchers concluded that this demonstrated that extroverted individuals look forward to meeting new people who appear friendly, while the introverted individuals either do not enjoy this or are more neutral in their response to such situations. T. Canli, H. Sivers, S. L. Whitfield, I. H. Gotlib, and J. D. E. Gabrieli. Amygdala Response to Happy Faces as a Function of Extraversion. Science Jun 21 2002: 2191.
Comment: Angry, threatening faces elicit the same fear response in all individuals tested, across all cultures tested. This indicates that this invariable response is necessary for survival. That is, it is an embedded response in each human. On the other hand, happy faces elicit different responses in different personality types. This indicates that variability in response to happy faces is adaptive. That is, in some situations it pays to be extroverted, but in other situations, a more introverted response (reserve and caution in an unfamiliar situation even if everyone appears friendly) may prove to be the more adaptive response. [“A man may smile, and smile and be a villain.” Shakespeare] For populations to successfully adapt to an unknown future, individuals within the population must exhibit a variety of emotional responses to the same situation. Cultures which tend to limit and constrain the preferred emotional responses of their populations, perhaps favoring extroverted responses to introverted ones, also limit the ability of their culture to adapt readily to changing circumstances.
Emotions and the Brain the AnthroHealth way: Each individual is born with a particular personality profile. We need to accept that variability in responses to certain situations is normal and potentially adaptive. A certain trait that does not appear at high frequency within a particular population is not necessarily an abnormal trait. In some cases, the uncommon trait could be the best, most adaptive, trait to have.
Egg Yolks and Infants: At around six months, infants begin to require nutritious foods in addition to breast milk. Since this is a period of rapid growth of both the body and the brain, it is important that weaning foods provide nutrients that adequately support such growth. Research has shown that egg yolks, particularly those fortified with omega 3 fatty acids, are a perfect weaning food because the egg yolks provide the brain and body with DHA [see the June newsletter] and iron; and they are very easy for young infants to eat and digest. Results of a study of infants who ate four egg yolks each week showed that their levels of iron and DHA were significantly elevated, but that there was no elevation in cholesterol levels compared to infants who did not eat any egg yolks. Makrides M, Hawkes JS, Neumann MA, Gibson RA. Nutritional effect of including egg yolk in the weaning diet of breast-fed and formula-fed infants: a randomized controlled trial. Am J Clin Nutr 2002 Jun;75(6):1084-92.
Egg Yolks and Infants the AnthroHealth Way: Egg yolks are excellent sources of protein and a variety of nutrients important to healthy infant growth and development. Soft boil an egg; remove and mash the yolk. Feed to infants every other day (4 times/week). Continue to breast feed until infant self-weans. In order to make sure her breast milk is as nutritious as possible, the mother should also eat eggs and fatty fish several times each week.
High Fiber and Menarche: Early menarche (girls age 12 or younger) can create both social and health problems (including a higher risk for breast cancer as an adult, possibly due to more years of exposing breast tissue to circulating estrogens). Researchers studied pre-menarcheal girls aged 6 – 14 for 5 years to determine whether diet was associated with age of onset of menarche. They found that girls with high fiber intake (greater than 25 gms each day) from eating fruits and vegetables had significantly lower risk for early onset menarche than did girls with a low fiber intake (less than 18 gms each day). This may be due to the fact that excess estrogen binds with fiber and is expelled from the body, thereby reducing its effects on the body. Girls who ate more monounsaturated fats, such as those found in tree nuts, also had a later age at menarche. Diets high in saturated fats, as opposed to mono- or polyunsaturated fats, are associated with weight gains which are turn in associated with higher levels of estrogens. A Western style diet of refined grain products and high fat dairy foods along with a very low intake of fruits, vegetables, tree nuts, and fatty fish is associated with early onset of menarche. Koo MM, Rohan TE, Jain M, McLaughlin JR, Corey PN. A cohort study of dietary fibre intake and menarche. Public Health Nutr 2002 Apr;5(2):353-60.
Comment: Menarche in foraging populations occurs at an average age of 15, which was also the average age of menarche in Western nations approximately 100 years ago. Since then, age at menarche has dropped in Western nations to an average of about 12.6 years. There is a period of infertility after menarche that averages about 18 months. In the past, this meant that a girl who went through menarche at age 15 would be unlikely to have a baby prior to age 17, an age at which most girls were considered women. These women also were usually in long-term relationships, generally marriage. Teens aged 16 – 19 have pregnancies and births that differ little, if at all, from those aged 20 – 24. This is not true for those younger than age 16 who are at high risk for problem pregnancies and births. A reduced age at menarche has led to a number of societal problems including that of children having children. Delaying menarche to age 14 or 15 would, therefore, have a number of benefits.
Menarche the AnthroHealth Way: The best way to ensure that a girl reaches menarche at an appropriate age is to have her eat the AnthroHealth Way from birth. She should be breast fed until self-weaned. Fruits, vegetables, tree nuts, fatty fish, shellfish, low fat fowl, and eggs should dominate her diet as she grows. Her intake of refined grain products, fast food, and high fat dairy products should be eliminated or severely restricted. She should exercise moderately, particularly by walking and swimming. Over-training in athletics can lead to an unnatural delay in onset of menarche which can also be harmful to health, particularly to the skeletal system. Balance is necessary.
AnthroHealth Tip of the Month: Since we are beginning the second half of the year, this month’s tip is a checklist to follow for maintaining optimal health.
© 2001-2009 Kathleen E. Fuller, PhD. All rights reserved.