Here are a few more scientific studies which could pass for the more outlandish claims of The GenoType Diet. Finger digit ratios (the comparison of the lengths of the ring and index fingers) correlate with other facial structures used in The GenoType Diet, such as jaw angle and other asymmetries. Put it all together and you get (drum roll, please):

A GenoType!

The second-to-fourth-digit ratio (2D:4D) may be related to prenatal testosterone and estrogen levels and pubertal face growth. Several studies have recently provided evidence that 2D:4D is associated with other-rated facial masculinity and dominance, but not with facialmetric measures of masculinity. We found that localized face shape differences, shown here to be sexually dimorphic* and related to ratings of dominance, were associated with direct and indirect measurements of 2D:4D. In this study we examined various localized features of the face, showing nose width, jaw angle, and lip height to be sexually dimorphic. We then had faces rated for dominance and saw that the most dimorphic characteristics were those most associated with rated dominance, with typically masculine characteristics tending to be associated with high ratings of dominance. Finally, 2D:4D measurements were made using three different techniques. High (feminine) values of 2D:4D were associated with feminine facial characteristics in women, but not in men. It was concluded that certain aspects of facial development are governed by factors that are established prenatally. These aspects may be associated with perceptions of the self by others that are important in the social environment, particularly in terms of intra-sexual competition and mate acquisition.

* Dimorphism is the systematic difference in form between individuals of different sex in the same species.

2D:4D and sexually dimorphic facial characteristics. Arch Sex Behav. 2007 Jun;36(3):377-84.

The average human male face differs from the average female face in size and shape of the jaws, cheek-bones, lips, eyes and nose. It is possible that this dimorphism is determined by sex steroids such as testosterone (T) and oestrogen (E), and several studies on the perception of such characteristics have been based on this assumption, but those studies focussed mainly on the relationship of male faces with circulating hormone levels; the corresponding biology of the female face remains mainly speculative. This paper is concerned with the relative importance of prenatal T and E levels (assessed via the 2D : 4D finger length ratio, a proxy for the ratio of T/E) and sex in the determination of facial form as characterized by 64 landmark points on facial photographs of 106 Austrians of college age. We found that (i) prenatal sex steroid ratios (in terms of 2D : 4D) and actual chromosomal sex dimorphism operate differently on faces, (ii) 2D : 4D affects male and female face shape by similar patterns, but (iii) is three times more intense in men than in women. There was no evidence that these effects were confounded by allometry or facial asymmetry. Our results suggest that studies on the perception of facial characteristics need to consider differential effects of prenatal hormone exposure and actual chromosomal gender in order to understand how characteristics have come to be rated 'masculine' or 'feminine' and the consequences of these perceptions in terms of mate preferences.

Second to fourth digit ratio and face shape. Proc Biol Sci. 2005 Oct 7;272(1576):1995-2001.

Sex steroids are supposed to moderate the differences between male and female facial characteristics. Studies on women's preferences for male faces reported increased preferences for facial architecture developed under the influence of testosterone as this may indicate masculinity, dominance and social status. Recent research demonstrates that facial sexual dimorphism does not only develop at puberty but may be organized much earlier in ontogeny. However, the actual cause and timing of variation in facial shape due to sex-steroids remains speculative. This study uses data from Neave and colleagues who measured digit ratio (2D:4D) as a proxy to prenatal testosterone and also salivary testosterone samples in order to study differential effects of androgens on perceived male facial shape. Male facial shape was regressed upon 2D:4D ratio and circulating levels of testosterone by means of geometric morphometric methods. We found some evidence for opposite effects of early androgen action (via 2D:4D ratio) on the upper and the lower face respectively (i.e. low 2D:4D ratio results in a relatively robust and prominent lower face), whereas circulating testosterone seems to cause a rather uniform elongation of the face. Local deformations primarily show pronounced and medially tailed eyebrows for the shapes associated with increasing salivary testosterone. These preliminary results suggest that prenatal and pubertal testosterone have differential effects on male facial shape that should be considered in future studies on women's preferences towards male facial appearance.

Visualizing facial shape regression upon 2nd to 4th digit ratio and testosterone. Coll Antropol. 2005 Dec;29(2):415-9.

Deviations of physical characteristics from bilateral symmetry, in otherwise symmetric individuals, are supposed to result from environmental perturbations during development. One cause of such perturbations may be sex steroids such as testosterone and estrogen. AIM: The study examined the relationship between second to fourth digit ratio (2D:4D), a putative negative correlate with prenatal testosterone and a positive correlate with prenatal estrogen, and asymmetry. METHODS: Eleven traits (including the second and fourth finger lengths) were measured in a sample of 680 English children aged 2-18 years, and second to fifth finger lengths in samples of 120 Austrian and English undergraduate students aged from 17 to 30 years and 213 Polish adults aged from 26 to 90 years. RESULTS: Significant U-shaped curvilinear associations between 2D:4D and all 11 traits were found in English children with the strongest associations between 2D:4D and composite asymmetry of second plus fourth digit, and second to fifth digits. Further investigation of the relation between 2D:4D and digit asymmetries in the sample of Austrian and English undergraduates and the Polish adults confirmed significant U-shaped relationships between 2D:4D and finger asymmetries. CONCLUSION: Our data show that both low 2D:4D (a marker of high prenatal testosterone) and high 2D:4D (a marker of high prenatal estrogen) are associated with elevated levels of asymmetry and this relationship applies particularly to finger asymmetry.

The second to fourth digit ratio and asymmetry. Ann Hum Biol. 2006 Jul-Aug;33(4):480-92.

Even USA Today is getting into the finger measuring business, though their recommended technique is not very accurate. And some of the more recent articles on epigenetics appearing in Medline are reading like sound bites for The GenoType Diet:

Medical practice patterns which are designed to provide quick and effective amelioration of signs and symptoms are frequently not an enduring solution to many health afflictions and chronic disease states. Recent scientific discovery has rendered the drug-oriented algorithmic paradigm commonly found in contemporary evidence-based medicine to be a reductionist approach to clinical practice. Unfolding evidence appears to support a genetic predisposition model of health and illness rather than a fatalistic predestination construct - modifiable epigenetic and environmental factors have enormous potential to influence clinical outcomes. By understanding and applying fundamental clinical principles relating to the emerging fields of molecular medicine, nutrigenomics and human exposure assessment, doctors will be empowered to address causality of affliction when possible and achieve sustained reprieve for many suffering patients.

-'Our genes are not our destiny: incorporating molecular medicine into clinical practice.' J Eval Clin Pract. 2008 Feb;14(1):94-102.

A wealth of evidence points to the diet as one of the most important modifiable determinants of the risk of developing cancer, but a greater understanding of the interaction between diet and genes may help distinguish who will and will not respond to dietary interventions. The term nutrigenomics or nutritional genomics refers to the bidirectional interactions between genes and diet. Nutritional genomics encompasses an understanding about how the response to bioactive food components depends on an individual's genetic background (nutrigenetics), nutrient induced changes in DNA methylation, histone posttranslational modifications, and other chromatin alterations (nutritional epigenetics), and nutrient induced changes in gene expression (nutritional transcriptomics). These approaches to the study of nutrition will assist in understanding how genetic variation, epigenetic events, and regulation of gene expression alter requirements for, and responses to, nutrients. Recognition of the interplay between genes and diet could ultimately help identify modifiable molecular targets for preventing, delaying, or reducing the symptoms of cancer and other chronic diseases.

'Nutritional genomic approaches to cancer prevention research.' Exp Oncol. 2007 Dec;29(4):250-6

Obesity and type 2 diabetes arise from a set of complex gene-environment interactions. Explanations for the heritability of these syndromes and the environmental contribution to disease susceptibility are addressed by the "thrifty genotype" and the "thrifty phenotype" hypotheses. Here, the merits of both models are discussed and elements of them are used to synthesize a "thrifty epigenotype" hypothesis. I propose that: (1) metabolic thrift, the capacity for efficient acquisition, storage and use of energy, is an ancient, complex trait, (2) the environmentally responsive gene network encoding this trait is subject to genetic canalization and thereby has become robust against mutational perturbations, (3) DNA sequence polymorphisms play a minor role in the aetiology of obesity and type 2 diabetes-instead, disease susceptibility is predominantly determined by epigenetic variations, (4) corresponding epigenotypes have the potential to be inherited across generations, and (5) Leptin is a candidate gene for the acquisition of a thrifty epigenotype.

'The thrifty epigenotype: An acquired and heritable predisposition for obesity and diabetes?' Bioessays. 2008 Feb;30(2):156-66.

Compared to other periods of life, infancy is a period of rapid growth, but the relative relationships among rates of linear growth, weight accretion and brain growth vary greatly during the first years of life. Additionally, while the energy requirements for body tissue deposition as a fraction of daily energy needs decrease dramatically during infancy, brain energy demands, measured as the cerebral rate of glucose utilization, increase markedly during the same period. There is now substantial evidence that postnatal growth in infancy is associated with various consequences detrimental to health in adult life, particularly hypertension, cardiovascular disease, obesity and type 2 diabetes, but the relationships vary depending on whether one takes growth to mean statural growth or ponderal growth, as well as on the specific period of infant growth. Recently, several mechanisms have surfaced that might account for the relationships observed. These include epigenetic effects on gene expression, alterations in neuronal signaling because of inappropriate dendritic pruning, and gut microbiota effects on fat storage.

'Growth in the first two years of life.' Nestle Nutr Workshop Ser Pediatr Program. 2008;61:135-44.

Twelve years ago when I was writing Eat Right For Your Type I used to Google (although there was no actual Google at the time; I used Excite) the phrases personalized medicine and personalized nutrition. At the time there were virtually no references. Now they number in the tens of thousands. However, Eat Right For Your Type was among the first books to ever use this concept.

With the The GenoType Diet, I've been instead googling the phrase Intergenerational Medicine and seeing about as much. Mark my words: in ten years you will see this phrase also appearing in the tens if not hundreds of thousands.

I often quote these citations when I lecture. Of course it would be most interesting to eventually learn what the author of the last abstract might consider an enriching experience.

Environmental influences can be inherited even without any mutations in the genes themselves. If genetic mutations are ‘typos' and relatively easy to test for, epigenetic changes are analogous to the formatting of the text (e.g. font, size, and color) and are much less well understood.

• Montague T. A New Way to Inherit Environmental Harm. Synthesis/Regeneration 39 (Winter 2006)

Mother rats exposed to hormone-mimicking chemicals during pregnancy gave birth to four successive generations of male offspring with significantly reduced fertility. Only the first generation of mothers was exposed to a toxin, yet four generations later the toxic effect could still be detected .

• M. Anway, A. Cupp, M. Uzumcu, and M. Skinner, Epigenetic Transgenerational Actions of Endocrine Disruptors and Male Fertility, Science Vol. 308, June 3, 2005, pp. 1466–1469.

Conceivably the cancer you may get today may have been caused by your grandmother's exposure to an industrial poison 50 years ago, even though your grandmother's genes were not changed by the exposure… or the mercury you're eating today in fish may not harm you directly, but may harm your grandchildren. These inherited traits can continue to influence the onset of diseases like diabetes, obesity, mental illness and heart disease, from generation to generation.

• Montague T. A New Way to Inherit Environmental Harm. Synthesis/Regeneration 39 (Winter 2006)

Global decrease in methylation levels is commonly observed in aging cells, as well as in neoplasia (early event.) The causes of this hypomethylation are not known. Contributes to chromosomal instability in cancer and to increased expression of selected affected genes. Unlike defective genes, which are damaged for life, methylated genes can be demethylated. And, methyl tags that are knocked off can be regained via nutrients, drugs, and enriching experiences.

• Asim K. Duttaroy Evolution, Epigenetics, and Maternal Nutrition 2006 Darwin Day Celebration.

Click on the image to listen to this broadcast.

A one-hour interview of Dr. Peter DAdamo by Cary Nostler of KSTE Radio, Sacramento California. The discussion includes the basics of blood type dieting, and how it lead to the development of Dr. D'Adamo's interest in epigenetics and The GenoType Diet.

Well, the cat's officially out of the bag. The GenoType Diet ships to all locations from here on in. I can't help wondering how it will be received. Like anything with beginnings an endings, you have to make see possibilities even in that which you compromise.

• The book had to be accurate and truthful, but you can't bury people with every single fact. Metaphors and parables can often be used to animate complex principles so they can be seen as the commonplace occurrences that they are.
• The book was written from a non-defensive standpoint. By that I mean, if it was important that something be said a certain way so as to make the point more intelligible by a larger audience, it was. Early on I decided to not write a book to please skeptics or critics of my earlier works. They would never be happy no matter what I would be willing to do, and besides, they wouldn't buy the book anyway.
• The book had to be helpful and prescriptive. It is not very useful to write a tome on how epigenetics interacts with the environment and not make it relevant to the reader in some simple way: perhaps the repurposing of a food or supplement, perhaps a whole new perspective on looking at their diet and lifestyle.
• The book had to be in sync with the past, but also unafraid to change as new facts and methods of analysis developed. Most long term readers will see a direct thread from GTD back to my earlier work with BTD. Others may be somewhat shaken by the difference that result from the new ways of analysis and classification. There are differences. Blood Type Dieting is a more 'idealizing model' and the GTD is a more 'abstracting model'. They get at their information from fundamentally different avenues of approach. Hopefully everyone who has an interest in this type of work will be able to find a spot along the continuum that is just right for them.

I think this is the most profound book I have authored, and it is the work I would like to be most remembered for. To take nothing away from the "Right For Your Type' books, I'm just a more mature author at this point in my life, and many things came together for this book that are dependent on being alive long enough to have a certain number of dreams. It was certainly the most difficult book I have every written. I felt from the beginning that this book had to be as perfect as I could get it, and I was lucky to have people around me who felt the same way. Whether any degree of perfection was actually achieved will have to wait for the test of time.

2.

Spent a pleasant morning yesterday with Mehmet Öz, his lovely wife Lisa and Michael Roizen. Mehmet has a radio show on XM that I was a guest on. I think it will air sometime mid January. Michael is the author of the 'Real Age' series of books, and together with Mehmet, they wrote a bestseller called YOU: On A Diet. Mehmet's wife Lisa was also part of the show. It was an interesting hour, and I was surprised by how much leeway I was given to go into some of the more technical aspects of the book. Both these guys are doctors and when their gears are turning you can see that they almost forget that they are doing a radio show.

3.

Christmas day dinner was delicious and made more pleasant by the return of our guests from last year. Jon Humberstone is the head of NAP customer service but in reality does incredibly much more than that. He does a lot of the back-end programming for the NAP e-store, and was critical in aligning the new NAP GenoType store with the genotypediet.com site. Keith McBride is our marketing wizard who made the liaison with Random House so breezy and effortless.

The guys gave me an unexpected but entirely welcome gift: Edward Tufte's Beautiful Evidence having read in a prior blog that I was especially fond of his earlier great work The Visual Display of Quantitative Information. I am so looking forward to curling up with this baby.